_

_

new _(value) → {Object}

Source:

Creates a lodash object which wraps value to enable implicit method chaining. Methods that operate on and return arrays, collections, and functions can be chained together. Methods that retrieve a single value or may return a primitive value will automatically end the chain sequence and return the unwrapped value. Otherwise, the value must be unwrapped with _#value.

Explicit chaining, which must be unwrapped with _#value in all cases, may be enabled using _.chain.

The execution of chained methods is lazy, that is, it's deferred until _#value is implicitly or explicitly called.

Lazy evaluation allows several methods to support shortcut fusion. Shortcut fusion is an optimization to merge iteratee calls; this avoids the creation of intermediate arrays and can greatly reduce the number of iteratee executions. Sections of a chain sequence qualify for shortcut fusion if the section is applied to an array of at least two hundred elements and any iteratees accept only one argument. The heuristic for whether a section qualifies for shortcut fusion is subject to change.

Chaining is supported in custom builds as long as the _#value method is directly or indirectly included in the build.

In addition to lodash methods, wrappers have Array and String methods.

The wrapper Array methods are: concat, join, pop, push, shift, sort, splice, and unshift

The wrapper String methods are: replace and split

The wrapper methods that support shortcut fusion are: at, compact, drop, dropRight, dropWhile, filter, find, findLast, head, initial, last, map, reject, reverse, slice, tail, take, takeRight, takeRightWhile, takeWhile, and toArray

The chainable wrapper methods are: after, ary, assign, assignIn, assignInWith, assignWith, at, before, bind, bindAll, bindKey, castArray, chain, chunk, commit, compact, concat, conforms, constant, countBy, create, curry, debounce, defaults, defaultsDeep, defer, delay, difference, differenceBy, differenceWith, drop, dropRight, dropRightWhile, dropWhile, fill, filter, flatten, flattenDeep, flattenDepth, flip, flow, flowRight, fromPairs, functions, functionsIn, groupBy, initial, intersection, intersectionBy, intersectionWith, invert, invertBy, invokeMap, iteratee, keyBy, keys, keysIn, map, mapKeys, mapValues, matches, matchesProperty, memoize, merge, mergeWith, method, methodOf, mixin, negate, nthArg, omit, omitBy, once, orderBy, over, overArgs, overEvery, overSome, partial, partialRight, partition, pick, pickBy, plant, property, propertyOf, pull, pullAll, pullAllBy, pullAt, push, range, rangeRight, rearg, reject, remove, rest, reverse, sampleSize, set, setWith, shuffle, slice, sort, sortBy, splice, spread, tail, take, takeRight, takeRightWhile, takeWhile, tap, throttle, thru, toArray, toPairs, toPairsIn, toPath, toPlainObject, transform, unary, union, unionBy, unionWith, uniq, uniqBy, uniqWith, unset, unshift, unzip, unzipWith, values, valuesIn, without, wrap, xor, xorBy, xorWith, zip, zipObject, zipObjectDeep, and zipWith

The wrapper methods that are not chainable by default are: add, attempt, camelCase, capitalize, ceil, clamp, clone, cloneDeep, cloneDeepWith, cloneWith, deburr, endsWith, eq, escape, escapeRegExp, every, find, findIndex, findKey, findLast, findLastIndex, findLastKey, floor, forEach, forEachRight, forIn, forInRight, forOwn, forOwnRight, get, gt, gte, has, hasIn, head, identity, includes, indexOf, inRange, invoke, isArguments, isArray, isArrayBuffer, isArrayLike, isArrayLikeObject, isBoolean, isBuffer, isDate, isElement, isEmpty, isEqual, isEqualWith, isError, isFinite, isFunction, isInteger, isLength, isMap, isMatch, isMatchWith, isNaN, isNative, isNil, isNull, isNumber, isObject, isObjectLike, isPlainObject, isRegExp, isSafeInteger, isSet, isString, isUndefined, isTypedArray, isWeakMap, isWeakSet, join, kebabCase, last, lastIndexOf, lowerCase, lowerFirst, lt, lte, max, maxBy, mean, min, minBy, noConflict, noop, now, pad, padEnd, padStart, parseInt, pop, random, reduce, reduceRight, repeat, result, round, runInContext, sample, shift, size, snakeCase, some, sortedIndex, sortedIndexBy, sortedLastIndex, sortedLastIndexBy, startCase, startsWith, subtract, sum, sumBy, template, times, toLower, toInteger, toLength, toNumber, toSafeInteger, toString, toUpper, trim, trimEnd, trimStart, truncate, unescape, uniqueId, upperCase, upperFirst, value, and words

Example
function square(n) {
  return n * n;
}

var wrapped = _([1, 2, 3]);

// Returns an unwrapped value.
wrapped.reduce(_.add);
// => 6

// Returns a wrapped value.
var squares = wrapped.map(square);

_.isArray(squares);
// => false

_.isArray(squares.value());
// => true
Parameters:
Name Type Description
value *

The value to wrap in a lodash instance.
Returns:

Returns the new lodash wrapper instance.

Type
Object

Members

(static) assign

Source:

Assigns own enumerable properties of source objects to the destination object. Source objects are applied from left to right. Subsequent sources overwrite property assignments of previous sources.

Note: This method mutates object and is loosely based on Object.assign.

Example
function Foo() {
  this.c = 3;
}

function Bar() {
  this.e = 5;
}

Foo.prototype.d = 4;
Bar.prototype.f = 6;

_.assign({ 'a': 1 }, new Foo, new Bar);
// => { 'a': 1, 'c': 3, 'e': 5 }

(static) assignWith

Source:

This method is like _.assign except that it accepts customizer which is invoked to produce the assigned values. If customizer returns undefined assignment is handled by the method instead. The customizer is invoked with five arguments: (objValue, srcValue, key, object, source).

Note: This method mutates object.

Example
function customizer(objValue, srcValue) {
  return _.isUndefined(objValue) ? srcValue : objValue;
}

var defaults = _.partialRight(_.assignWith, customizer);

defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
// => { 'a': 1, 'b': 2 }

(static) at

Source:

This method is the wrapper version of _.at.

Example
var object = { 'a': [{ 'b': { 'c': 3 } }, 4] };

_(object).at(['a[0].b.c', 'a[1]']).value();
// => [3, 4]

_(['a', 'b', 'c']).at(0, 2).value();
// => ['a', 'c']

(static) at

Source:

Creates an array of values corresponding to paths of object.

Example
var object = { 'a': [{ 'b': { 'c': 3 } }, 4] };

_.at(object, ['a[0].b.c', 'a[1]']);
// => [3, 4]

_.at(['a', 'b', 'c'], 0, 2);
// => ['a', 'c']

(static) attempt

Source:

Attempts to invoke func, returning either the result or the caught error object. Any additional arguments are provided to func when it's invoked.

Example
// Avoid throwing errors for invalid selectors.
var elements = _.attempt(function(selector) {
  return document.querySelectorAll(selector);
}, '>_>');

if (_.isError(elements)) {
  elements = [];
}

(static) bind

Source:

Creates a function that invokes func with the this binding of thisArg and prepends any additional _.bind arguments to those provided to the bound function.

The _.bind.placeholder value, which defaults to _ in monolithic builds, may be used as a placeholder for partially applied arguments.

Note: Unlike native Function#bind this method doesn't set the "length" property of bound functions.

Example
var greet = function(greeting, punctuation) {
  return greeting + ' ' + this.user + punctuation;
};

var object = { 'user': 'fred' };

var bound = _.bind(greet, object, 'hi');
bound('!');
// => 'hi fred!'

// Bound with placeholders.
var bound = _.bind(greet, object, _, '!');
bound('hi');
// => 'hi fred!'

(static) bindAll

Source:

Binds methods of an object to the object itself, overwriting the existing method.

Note: This method doesn't set the "length" property of bound functions.

Example
var view = {
  'label': 'docs',
  'onClick': function() {
    console.log('clicked ' + this.label);
  }
};

_.bindAll(view, 'onClick');
jQuery(element).on('click', view.onClick);
// => logs 'clicked docs' when clicked

(static) bindKey

Source:

Creates a function that invokes the method at object[key] and prepends any additional _.bindKey arguments to those provided to the bound function.

This method differs from _.bind by allowing bound functions to reference methods that may be redefined or don't yet exist. See Peter Michaux's article for more details.

The _.bindKey.placeholder value, which defaults to _ in monolithic builds, may be used as a placeholder for partially applied arguments.

Example
var object = {
  'user': 'fred',
  'greet': function(greeting, punctuation) {
    return greeting + ' ' + this.user + punctuation;
  }
};

var bound = _.bindKey(object, 'greet', 'hi');
bound('!');
// => 'hi fred!'

object.greet = function(greeting, punctuation) {
  return greeting + 'ya ' + this.user + punctuation;
};

bound('!');
// => 'hiya fred!'

// Bound with placeholders.
var bound = _.bindKey(object, 'greet', _, '!');
bound('hi');
// => 'hiya fred!'

(static) camelCase

Source:

Converts string to camel case.

Example
_.camelCase('Foo Bar');
// => 'fooBar'

_.camelCase('--foo-bar');
// => 'fooBar'

_.camelCase('__foo_bar__');
// => 'fooBar'

(static) ceil

Source:

Computes number rounded up to precision.

Example
_.ceil(4.006);
// => 5

_.ceil(6.004, 2);
// => 6.01

_.ceil(6040, -2);
// => 6100

(static) chain

Source:

Enables explicit method chaining on the wrapper object.

Example
var users = [
  { 'user': 'barney', 'age': 36 },
  { 'user': 'fred',   'age': 40 }
];

// A sequence without explicit chaining.
_(users).head();
// => { 'user': 'barney', 'age': 36 }

// A sequence with explicit chaining.
_(users)
  .chain()
  .head()
  .pick('user')
  .value();
// => { 'user': 'barney' }

(static) commit

Source:

Executes the chained sequence and returns the wrapped result.

Example
var array = [1, 2];
var wrapped = _(array).push(3);

console.log(array);
// => [1, 2]

wrapped = wrapped.commit();
console.log(array);
// => [1, 2, 3]

wrapped.last();
// => 3

console.log(array);
// => [1, 2, 3]

(static) concat

Source:

Creates a new array concatenating array with any additional arrays and/or values.

Example
var array = [1];
var other = _.concat(array, 2, [3], [[4]]);

console.log(other);
// => [1, 2, 3, [4]]

console.log(array);
// => [1]

(static) countBy

Source:

Creates an object composed of keys generated from the results of running each element of collection through iteratee. The corresponding value of each key is the number of times the key was returned by iteratee. The iteratee is invoked with one argument: (value).

Example
_.countBy([6.1, 4.2, 6.3], Math.floor);
// => { '4': 1, '6': 2 }

_.countBy(['one', 'two', 'three'], 'length');
// => { '3': 2, '5': 1 }

(static) defaults

Source:

Assigns own and inherited enumerable properties of source objects to the destination object for all destination properties that resolve to undefined. Source objects are applied from left to right. Once a property is set, additional values of the same property are ignored.

Note: This method mutates object.

Example
_.defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
// => { 'user': 'barney', 'age': 36 }

(static) defaultsDeep

Source:

This method is like _.defaults except that it recursively assigns default properties.

Note: This method mutates object.

Example
_.defaultsDeep({ 'user': { 'name': 'barney' } }, { 'user': { 'name': 'fred', 'age': 36 } });
// => { 'user': { 'name': 'barney', 'age': 36 } }

(static) defer

Source:

Defers invoking the func until the current call stack has cleared. Any additional arguments are provided to func when it's invoked.

Example
_.defer(function(text) {
  console.log(text);
}, 'deferred');
// => logs 'deferred' after one or more milliseconds

(static) delay

Source:

Invokes func after wait milliseconds. Any additional arguments are provided to func when it's invoked.

Example
_.delay(function(text) {
  console.log(text);
}, 1000, 'later');
// => logs 'later' after one second

(static) difference

Source:

Creates an array of unique array values not included in the other given arrays using SameValueZero for equality comparisons.

Example
_.difference([3, 2, 1], [4, 2]);
// => [3, 1]

(static) differenceBy

Source:

This method is like _.difference except that it accepts iteratee which is invoked for each element of array and values to generate the criterion by which uniqueness is computed. The iteratee is invoked with one argument: (value).

Example
_.differenceBy([3.1, 2.2, 1.3], [4.4, 2.5], Math.floor);
// => [3.1, 1.3]

// The `_.property` iteratee shorthand.
_.differenceBy([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], 'x');
// => [{ 'x': 2 }]

(static) differenceWith

Source:

This method is like _.difference except that it accepts comparator which is invoked to compare elements of array to values. The comparator is invoked with two arguments: (arrVal, othVal).

Example
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];

_.differenceWith(objects, [{ 'x': 1, 'y': 2 }], _.isEqual);
// => [{ 'x': 2, 'y': 1 }]

(static) extend

Source:

This method is like _.assign except that it iterates over own and inherited source properties.

Note: This method mutates object.

Example
function Foo() {
  this.b = 2;
}

function Bar() {
  this.d = 4;
}

Foo.prototype.c = 3;
Bar.prototype.e = 5;

_.assignIn({ 'a': 1 }, new Foo, new Bar);
// => { 'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5 }

(static) extendWith

Source:

This method is like _.assignIn except that it accepts customizer which is invoked to produce the assigned values. If customizer returns undefined assignment is handled by the method instead. The customizer is invoked with five arguments: (objValue, srcValue, key, object, source).

Note: This method mutates object.

Example
function customizer(objValue, srcValue) {
  return _.isUndefined(objValue) ? srcValue : objValue;
}

var defaults = _.partialRight(_.assignInWith, customizer);

defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
// => { 'a': 1, 'b': 2 }

(static) flatMap

Source:

This method is the wrapper version of _.flatMap.

Example
function duplicate(n) {
  return [n, n];
}

_([1, 2]).flatMap(duplicate).value();
// => [1, 1, 2, 2]

(static) floor

Source:

Computes number rounded down to precision.

Example
_.floor(4.006);
// => 4

_.floor(0.046, 2);
// => 0.04

_.floor(4060, -2);
// => 4000

(static) flow

Source:

Creates a function that returns the result of invoking the given functions with the this binding of the created function, where each successive invocation is supplied the return value of the previous.

Example
function square(n) {
  return n * n;
}

var addSquare = _.flow(_.add, square);
addSquare(1, 2);
// => 9

(static) flowRight

Source:

This method is like _.flow except that it creates a function that invokes the given functions from right to left.

Example
function square(n) {
  return n * n;
}

var addSquare = _.flowRight(square, _.add);
addSquare(1, 2);
// => 9

(static) groupBy

Source:

Creates an object composed of keys generated from the results of running each element of collection through iteratee. The corresponding value of each key is an array of elements responsible for generating the key. The iteratee is invoked with one argument: (value).

Example
_.groupBy([6.1, 4.2, 6.3], Math.floor);
// => { '4': [4.2], '6': [6.1, 6.3] }

// The `_.property` iteratee shorthand.
_.groupBy(['one', 'two', 'three'], 'length');
// => { '3': ['one', 'two'], '5': ['three'] }

(static) intersection

Source:

Creates an array of unique values that are included in all given arrays using SameValueZero for equality comparisons.

Example
_.intersection([2, 1], [4, 2], [1, 2]);
// => [2]

(static) intersectionBy

Source:

This method is like _.intersection except that it accepts iteratee which is invoked for each element of each arrays to generate the criterion by which uniqueness is computed. The iteratee is invoked with one argument: (value).

Example
_.intersectionBy([2.1, 1.2], [4.3, 2.4], Math.floor);
// => [2.1]

// The `_.property` iteratee shorthand.
_.intersectionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 1 }]

(static) intersectionWith

Source:

This method is like _.intersection except that it accepts comparator which is invoked to compare elements of arrays. The comparator is invoked with two arguments: (arrVal, othVal).

Example
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.intersectionWith(objects, others, _.isEqual);
// => [{ 'x': 1, 'y': 2 }]

(static) invert

Source:

Creates an object composed of the inverted keys and values of object. If object contains duplicate values, subsequent values overwrite property assignments of previous values.

Example
var object = { 'a': 1, 'b': 2, 'c': 1 };

_.invert(object);
// => { '1': 'c', '2': 'b' }

(static) invertBy

Source:

This method is like _.invert except that the inverted object is generated from the results of running each element of object through iteratee. The corresponding inverted value of each inverted key is an array of keys responsible for generating the inverted value. The iteratee is invoked with one argument: (value).

Example
var object = { 'a': 1, 'b': 2, 'c': 1 };

_.invertBy(object);
// => { '1': ['a', 'c'], '2': ['b'] }

_.invertBy(object, function(value) {
  return 'group' + value;
});
// => { 'group1': ['a', 'c'], 'group2': ['b'] }

(static) invoke

Source:

Invokes the method at path of object.

Example
var object = { 'a': [{ 'b': { 'c': [1, 2, 3, 4] } }] };

_.invoke(object, 'a[0].b.c.slice', 1, 3);
// => [2, 3]

(static) invokeMap

Source:

Invokes the method at path of each element in collection, returning an array of the results of each invoked method. Any additional arguments are provided to each invoked method. If methodName is a function it's invoked for, and this bound to, each element in collection.

Example
_.invokeMap([[5, 1, 7], [3, 2, 1]], 'sort');
// => [[1, 5, 7], [1, 2, 3]]

_.invokeMap([123, 456], String.prototype.split, '');
// => [['1', '2', '3'], ['4', '5', '6']]

(static) isArray :function

Source:

Checks if value is classified as an Array object.

Type:
  • function
Example
_.isArray([1, 2, 3]);
// => true

_.isArray(document.body.children);
// => false

_.isArray('abc');
// => false

_.isArray(_.noop);
// => false

(static) isBuffer

Source:

Checks if value is a buffer.

Example
_.isBuffer(new Buffer(2));
// => true

_.isBuffer(new Uint8Array(2));
// => false

(static) kebabCase

Source:

Converts string to kebab case.

Example
_.kebabCase('Foo Bar');
// => 'foo-bar'

_.kebabCase('fooBar');
// => 'foo-bar'

_.kebabCase('__foo_bar__');
// => 'foo-bar'

(static) keyBy

Source:

Creates an object composed of keys generated from the results of running each element of collection through iteratee. The corresponding value of each key is the last element responsible for generating the key. The iteratee is invoked with one argument: (value).

Example
var array = [
  { 'dir': 'left', 'code': 97 },
  { 'dir': 'right', 'code': 100 }
];

_.keyBy(array, function(o) {
  return String.fromCharCode(o.code);
});
// => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }

_.keyBy(array, 'dir');
// => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }

(static) lowerCase

Source:

Converts string, as space separated words, to lower case.

Example
_.lowerCase('--Foo-Bar');
// => 'foo bar'

_.lowerCase('fooBar');
// => 'foo bar'

_.lowerCase('__FOO_BAR__');
// => 'foo bar'

(static) lowerFirst

Source:

Converts the first character of string to lower case.

Example
_.lowerFirst('Fred');
// => 'fred'

_.lowerFirst('FRED');
// => 'fRED'

(static) merge

Source:

Recursively merges own and inherited enumerable properties of source objects into the destination object. Source properties that resolve to undefined are skipped if a destination value exists. Array and plain object properties are merged recursively. Other objects and value types are overridden by assignment. Source objects are applied from left to right. Subsequent sources overwrite property assignments of previous sources.

Note: This method mutates object.

Example
var users = {
  'data': [{ 'user': 'barney' }, { 'user': 'fred' }]
};

var ages = {
  'data': [{ 'age': 36 }, { 'age': 40 }]
};

_.merge(users, ages);
// => { 'data': [{ 'user': 'barney', 'age': 36 }, { 'user': 'fred', 'age': 40 }] }

(static) mergeWith

Source:

This method is like _.merge except that it accepts customizer which is invoked to produce the merged values of the destination and source properties. If customizer returns undefined merging is handled by the method instead. The customizer is invoked with seven arguments: (objValue, srcValue, key, object, source, stack).

Note: This method mutates object.

Example
function customizer(objValue, srcValue) {
  if (_.isArray(objValue)) {
    return objValue.concat(srcValue);
  }
}

var object = {
  'fruits': ['apple'],
  'vegetables': ['beet']
};

var other = {
  'fruits': ['banana'],
  'vegetables': ['carrot']
};

_.mergeWith(object, other, customizer);
// => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot'] }

(static) method

Source:

Creates a function that invokes the method at path of a given object. Any additional arguments are provided to the invoked method.

Example
var objects = [
  { 'a': { 'b': { 'c': _.constant(2) } } },
  { 'a': { 'b': { 'c': _.constant(1) } } }
];

_.map(objects, _.method('a.b.c'));
// => [2, 1]

_.invokeMap(_.sortBy(objects, _.method(['a', 'b', 'c'])), 'a.b.c');
// => [1, 2]

(static) methodOf

Source:

The opposite of _.method; this method creates a function that invokes the method at a given path of object. Any additional arguments are provided to the invoked method.

Example
var array = _.times(3, _.constant),
    object = { 'a': array, 'b': array, 'c': array };

_.map(['a[2]', 'c[0]'], _.methodOf(object));
// => [2, 0]

_.map([['a', '2'], ['c', '0']], _.methodOf(object));
// => [2, 0]

(static) next

Source:

Gets the next value on a wrapped object following the iterator protocol.

Example
var wrapped = _([1, 2]);

wrapped.next();
// => { 'done': false, 'value': 1 }

wrapped.next();
// => { 'done': false, 'value': 2 }

wrapped.next();
// => { 'done': true, 'value': undefined }

(static) now :function

Source:

Gets the timestamp of the number of milliseconds that have elapsed since the Unix epoch (1 January 1970 00:00:00 UTC).

Type:
  • function
Example
_.defer(function(stamp) {
  console.log(_.now() - stamp);
}, _.now());
// => logs the number of milliseconds it took for the deferred function to be invoked

(static) omit

Source:

The opposite of _.pick; this method creates an object composed of the own and inherited enumerable properties of object that are not omitted.

Example
var object = { 'a': 1, 'b': '2', 'c': 3 };

_.omit(object, ['a', 'c']);
// => { 'b': '2' }

(static) over

Source:

Creates a function that invokes iteratees with the arguments provided to the created function and returns their results.

Example
var func = _.over(Math.max, Math.min);

func(1, 2, 3, 4);
// => [4, 1]

(static) overArgs

Source:

Creates a function that invokes func with arguments transformed by corresponding transforms.

Example
function doubled(n) {
  return n * 2;
}

function square(n) {
  return n * n;
}

var func = _.overArgs(function(x, y) {
  return [x, y];
}, square, doubled);

func(9, 3);
// => [81, 6]

func(10, 5);
// => [100, 10]

(static) overEvery

Source:

Creates a function that checks if all of the predicates return truthy when invoked with the arguments provided to the created function.

Example
var func = _.overEvery(Boolean, isFinite);

func('1');
// => true

func(null);
// => false

func(NaN);
// => false

(static) overSome

Source:

Creates a function that checks if any of the predicates return truthy when invoked with the arguments provided to the created function.

Example
var func = _.overSome(Boolean, isFinite);

func('1');
// => true

func(null);
// => true

func(NaN);
// => false

(static) partial

Source:

Creates a function that invokes func with partial arguments prepended to those provided to the new function. This method is like _.bind except it does not alter the this binding.

The _.partial.placeholder value, which defaults to _ in monolithic builds, may be used as a placeholder for partially applied arguments.

Note: This method doesn't set the "length" property of partially applied functions.

Example
var greet = function(greeting, name) {
  return greeting + ' ' + name;
};

var sayHelloTo = _.partial(greet, 'hello');
sayHelloTo('fred');
// => 'hello fred'

// Partially applied with placeholders.
var greetFred = _.partial(greet, _, 'fred');
greetFred('hi');
// => 'hi fred'

(static) partialRight

Source:

This method is like _.partial except that partially applied arguments are appended to those provided to the new function.

The _.partialRight.placeholder value, which defaults to _ in monolithic builds, may be used as a placeholder for partially applied arguments.

Note: This method doesn't set the "length" property of partially applied functions.

Example
var greet = function(greeting, name) {
  return greeting + ' ' + name;
};

var greetFred = _.partialRight(greet, 'fred');
greetFred('hi');
// => 'hi fred'

// Partially applied with placeholders.
var sayHelloTo = _.partialRight(greet, 'hello', _);
sayHelloTo('fred');
// => 'hello fred'

(static) partition

Source:

Creates an array of elements split into two groups, the first of which contains elements predicate returns truthy for, the second of which contains elements predicate returns falsey for. The predicate is invoked with one argument: (value).

Example
var users = [
  { 'user': 'barney',  'age': 36, 'active': false },
  { 'user': 'fred',    'age': 40, 'active': true },
  { 'user': 'pebbles', 'age': 1,  'active': false }
];

_.partition(users, function(o) { return o.active; });
// => objects for [['fred'], ['barney', 'pebbles']]

// The `_.matches` iteratee shorthand.
_.partition(users, { 'age': 1, 'active': false });
// => objects for [['pebbles'], ['barney', 'fred']]

// The `_.matchesProperty` iteratee shorthand.
_.partition(users, ['active', false]);
// => objects for [['barney', 'pebbles'], ['fred']]

// The `_.property` iteratee shorthand.
_.partition(users, 'active');
// => objects for [['fred'], ['barney', 'pebbles']]

(static) pick

Source:

Creates an object composed of the picked object properties.

Example
var object = { 'a': 1, 'b': '2', 'c': 3 };

_.pick(object, ['a', 'c']);
// => { 'a': 1, 'c': 3 }

(static) plant

Source:

Creates a clone of the chained sequence planting value as the wrapped value.

Example
function square(n) {
  return n * n;
}

var wrapped = _([1, 2]).map(square);
var other = wrapped.plant([3, 4]);

other.value();
// => [9, 16]

wrapped.value();
// => [1, 4]

(static) pull

Source:

Removes all given values from array using SameValueZero for equality comparisons.

Note: Unlike _.without, this method mutates array. Use _.remove to remove elements from an array by predicate.

Example
var array = [1, 2, 3, 1, 2, 3];

_.pull(array, 2, 3);
console.log(array);
// => [1, 1]

(static) pullAt

Source:

Removes elements from array corresponding to indexes and returns an array of removed elements.

Note: Unlike _.at, this method mutates array.

Example
var array = [5, 10, 15, 20];
var evens = _.pullAt(array, 1, 3);

console.log(array);
// => [5, 15]

console.log(evens);
// => [10, 20]

(static) range

Source:

Creates an array of numbers (positive and/or negative) progressing from start up to, but not including, end. A step of -1 is used if a negative start is specified without an end or step. If end is not specified it's set to start with start then set to 0.

Note: JavaScript follows the IEEE-754 standard for resolving floating-point values which can produce unexpected results.

Example
_.range(4);
// => [0, 1, 2, 3]

_.range(-4);
// => [0, -1, -2, -3]

_.range(1, 5);
// => [1, 2, 3, 4]

_.range(0, 20, 5);
// => [0, 5, 10, 15]

_.range(0, -4, -1);
// => [0, -1, -2, -3]

_.range(1, 4, 0);
// => [1, 1, 1]

_.range(0);
// => []

(static) rangeRight

Source:

This method is like _.range except that it populates values in descending order.

Example
_.rangeRight(4);
// => [3, 2, 1, 0]

_.rangeRight(-4);
// => [-3, -2, -1, 0]

_.rangeRight(1, 5);
// => [4, 3, 2, 1]

_.rangeRight(0, 20, 5);
// => [15, 10, 5, 0]

_.rangeRight(0, -4, -1);
// => [-3, -2, -1, 0]

_.rangeRight(1, 4, 0);
// => [1, 1, 1]

_.rangeRight(0);
// => []

(static) rearg

Source:

Creates a function that invokes func with arguments arranged according to the specified indexes where the argument value at the first index is provided as the first argument, the argument value at the second index is provided as the second argument, and so on.

Example
var rearged = _.rearg(function(a, b, c) {
  return [a, b, c];
}, 2, 0, 1);

rearged('b', 'c', 'a')
// => ['a', 'b', 'c']

(static) reverse

Source:

This method is the wrapper version of _.reverse.

Note: This method mutates the wrapped array.

Example
var array = [1, 2, 3];

_(array).reverse().value()
// => [3, 2, 1]

console.log(array);
// => [3, 2, 1]

(static) round

Source:

Computes number rounded to precision.

Example
_.round(4.006);
// => 4

_.round(4.006, 2);
// => 4.01

_.round(4060, -2);
// => 4100

(static) snakeCase

Source:

Converts string to snake case.

Example
_.snakeCase('Foo Bar');
// => 'foo_bar'

_.snakeCase('fooBar');
// => 'foo_bar'

_.snakeCase('--foo-bar');
// => 'foo_bar'

(static) sortBy

Source:

Creates an array of elements, sorted in ascending order by the results of running each element in a collection through each iteratee. This method performs a stable sort, that is, it preserves the original sort order of equal elements. The iteratees are invoked with one argument: (value).

Example
var users = [
  { 'user': 'fred',   'age': 48 },
  { 'user': 'barney', 'age': 36 },
  { 'user': 'fred',   'age': 42 },
  { 'user': 'barney', 'age': 34 }
];

_.sortBy(users, function(o) { return o.user; });
// => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]

_.sortBy(users, ['user', 'age']);
// => objects for [['barney', 34], ['barney', 36], ['fred', 42], ['fred', 48]]

_.sortBy(users, 'user', function(o) {
  return Math.floor(o.age / 10);
});
// => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]

(static) startCase

Source:

Converts string to start case.

Example
_.startCase('--foo-bar');
// => 'Foo Bar'

_.startCase('fooBar');
// => 'Foo Bar'

_.startCase('__foo_bar__');
// => 'Foo Bar'

(static) union

Source:

Creates an array of unique values, in order, from all given arrays using SameValueZero for equality comparisons.

Example
_.union([2, 1], [4, 2], [1, 2]);
// => [2, 1, 4]

(static) unionBy

Source:

This method is like _.union except that it accepts iteratee which is invoked for each element of each arrays to generate the criterion by which uniqueness is computed. The iteratee is invoked with one argument: (value).

Example
_.unionBy([2.1, 1.2], [4.3, 2.4], Math.floor);
// => [2.1, 1.2, 4.3]

// The `_.property` iteratee shorthand.
_.unionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 1 }, { 'x': 2 }]

(static) unionWith

Source:

This method is like _.union except that it accepts comparator which is invoked to compare elements of arrays. The comparator is invoked with two arguments: (arrVal, othVal).

Example
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.unionWith(objects, others, _.isEqual);
// => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 1 }]

(static) upperCase

Source:

Converts string, as space separated words, to upper case.

Example
_.upperCase('--foo-bar');
// => 'FOO BAR'

_.upperCase('fooBar');
// => 'FOO BAR'

_.upperCase('__foo_bar__');
// => 'FOO BAR'

(static) upperFirst

Source:

Converts the first character of string to upper case.

Example
_.upperFirst('fred');
// => 'Fred'

_.upperFirst('FRED');
// => 'FRED'

(static) value

Source:

Executes the chained sequence to extract the unwrapped value.

Example
_([1, 2, 3]).value();
// => [1, 2, 3]

(static) without

Source:

Creates an array excluding all given values using SameValueZero for equality comparisons.

Example
_.without([1, 2, 1, 3], 1, 2);
// => [3]

(static) xor

Source:

Creates an array of unique values that is the symmetric difference of the given arrays.

Example
_.xor([2, 1], [4, 2]);
// => [1, 4]

(static) xorBy

Source:

This method is like _.xor except that it accepts iteratee which is invoked for each element of each arrays to generate the criterion by which uniqueness is computed. The iteratee is invoked with one argument: (value).

Example
_.xorBy([2.1, 1.2], [4.3, 2.4], Math.floor);
// => [1.2, 4.3]

// The `_.property` iteratee shorthand.
_.xorBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 2 }]

(static) xorWith

Source:

This method is like _.xor except that it accepts comparator which is invoked to compare elements of arrays. The comparator is invoked with two arguments: (arrVal, othVal).

Example
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.xorWith(objects, others, _.isEqual);
// => [{ 'x': 2, 'y': 1 }, { 'x': 1, 'y': 1 }]

(static) zip

Source:

Creates an array of grouped elements, the first of which contains the first elements of the given arrays, the second of which contains the second elements of the given arrays, and so on.

Example
_.zip(['fred', 'barney'], [30, 40], [true, false]);
// => [['fred', 30, true], ['barney', 40, false]]

(static) zipWith

Source:

This method is like _.zip except that it accepts iteratee to specify how grouped values should be combined. The iteratee is invoked with the elements of each group: (...group).

Example
_.zipWith([1, 2], [10, 20], [100, 200], function(a, b, c) {
  return a + b + c;
});
// => [111, 222]

Methods

(static) add(augend, addend) → {number}

Source:

Adds two numbers.

Example
_.add(6, 4);
// => 10
Parameters:
Name Type Description
augend number

The first number in an addition.
addend number

The second number in an addition.
Returns:

Returns the total.

Type
number

(static) after(n, func) → {function}

Source:

The opposite of _.before; this method creates a function that invokes func once it's called n or more times.

Example
var saves = ['profile', 'settings'];

var done = _.after(saves.length, function() {
  console.log('done saving!');
});

_.forEach(saves, function(type) {
  asyncSave({ 'type': type, 'complete': done });
});
// => logs 'done saving!' after the two async saves have completed
Parameters:
Name Type Description
n number

The number of calls before func is invoked.
func function

The function to restrict.
Returns:

Returns the new restricted function.

Type
function

(static) ary(func, nopt) → {function}

Source:

Creates a function that accepts up to n arguments, ignoring any additional arguments.

Example
_.map(['6', '8', '10'], _.ary(parseInt, 1));
// => [6, 8, 10]
Parameters:
Name Type Attributes Default Description
func function

The function to cap arguments for.
n number <optional>
 func.length

The arity cap.
Returns:

Returns the new function.

Type
function

(static) before(n, func) → {function}

Source:

Creates a function that invokes func, with the this binding and arguments of the created function, while it's called less than n times. Subsequent calls to the created function return the result of the last func invocation.

Example
jQuery(element).on('click', _.before(5, addContactToList));
// => allows adding up to 4 contacts to the list
Parameters:
Name Type Description
n number

The number of calls at which func is no longer invoked.
func function

The function to restrict.
Returns:

Returns the new restricted function.

Type
function

(static) capitalize(stringopt) → {string}

Source:

Converts the first character of string to upper case and the remaining to lower case.

Example
_.capitalize('FRED');
// => 'Fred'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to capitalize.
Returns:

Returns the capitalized string.

Type
string

(static) castArray(value) → {Array}

Source:

Casts value as an array if it's not one.

Example
_.castArray(1);
// => [1]

_.castArray({ 'a': 1 });
// => [{ 'a': 1 }]

_.castArray('abc');
// => ['abc']

_.castArray(null);
// => [null]

_.castArray(undefined);
// => [undefined]

_.castArray();
// => []

var array = [1, 2, 3];
console.log(_.castArray(array) === array);
// => true
Parameters:
Name Type Description
value *

The value to inspect.
Returns:

Returns the cast array.

Type
Array

(static) chain(value) → {Object}

Source:

Creates a lodash object that wraps value with explicit method chaining enabled. The result of such method chaining must be unwrapped with _#value.

Example
var users = [
  { 'user': 'barney',  'age': 36 },
  { 'user': 'fred',    'age': 40 },
  { 'user': 'pebbles', 'age': 1 }
];

var youngest = _
  .chain(users)
  .sortBy('age')
  .map(function(o) {
    return o.user + ' is ' + o.age;
  })
  .head()
  .value();
// => 'pebbles is 1'
Parameters:
Name Type Description
value *

The value to wrap.
Returns:

Returns the new lodash wrapper instance.

Type
Object

(static) chunk(array, sizeopt) → {Array}

Source:

Creates an array of elements split into groups the length of size. If array can't be split evenly, the final chunk will be the remaining elements.

Example
_.chunk(['a', 'b', 'c', 'd'], 2);
// => [['a', 'b'], ['c', 'd']]

_.chunk(['a', 'b', 'c', 'd'], 3);
// => [['a', 'b', 'c'], ['d']]
Parameters:
Name Type Attributes Default Description
array Array

The array to process.
size number <optional>
 0

The length of each chunk.
Returns:

Returns the new array containing chunks.

Type
Array

(static) clamp(number, loweropt, upper) → {number}

Source:

Clamps number within the inclusive lower and upper bounds.

Example
_.clamp(-10, -5, 5);
// => -5

_.clamp(10, -5, 5);
// => 5
Parameters:
Name Type Attributes Description
number number

The number to clamp.
lower number <optional>

The lower bound.
upper number

The upper bound.
Returns:

Returns the clamped number.

Type
number

(static) clone(value) → {*}

Source:

Creates a shallow clone of value.

Note: This method is loosely based on the structured clone algorithm and supports cloning arrays, array buffers, booleans, date objects, maps, numbers, Object objects, regexes, sets, strings, symbols, and typed arrays. The own enumerable properties of arguments objects are cloned as plain objects. An empty object is returned for uncloneable values such as error objects, functions, DOM nodes, and WeakMaps.

Example
var objects = [{ 'a': 1 }, { 'b': 2 }];

var shallow = _.clone(objects);
console.log(shallow[0] === objects[0]);
// => true
Parameters:
Name Type Description
value *

The value to clone.
Returns:

Returns the cloned value.

Type
*

(static) cloneDeep(value) → {*}

Source:

This method is like _.clone except that it recursively clones value.

Example
var objects = [{ 'a': 1 }, { 'b': 2 }];

var deep = _.cloneDeep(objects);
console.log(deep[0] === objects[0]);
// => false
Parameters:
Name Type Description
value *

The value to recursively clone.
Returns:

Returns the deep cloned value.

Type
*

(static) cloneDeepWith(value, customizeropt) → {*}

Source:

This method is like _.cloneWith except that it recursively clones value.

Example
function customizer(value) {
  if (_.isElement(value)) {
    return value.cloneNode(true);
  }
}

var el = _.cloneDeepWith(document.body, customizer);

console.log(el === document.body);
// => false
console.log(el.nodeName);
// => 'BODY'
console.log(el.childNodes.length);
// => 20
Parameters:
Name Type Attributes Description
value *

The value to recursively clone.
customizer function <optional>

The function to customize cloning.
Returns:

Returns the deep cloned value.

Type
*

(static) cloneWith(value, customizeropt) → {*}

Source:

This method is like _.clone except that it accepts customizer which is invoked to produce the cloned value. If customizer returns undefined cloning is handled by the method instead. The customizer is invoked with up to four arguments; (value [, index|key, object, stack]).

Example
function customizer(value) {
  if (_.isElement(value)) {
    return value.cloneNode(false);
  }
}

var el = _.cloneWith(document.body, customizer);

console.log(el === document.body);
// => false
console.log(el.nodeName);
// => 'BODY'
console.log(el.childNodes.length);
// => 0
Parameters:
Name Type Attributes Description
value *

The value to clone.
customizer function <optional>

The function to customize cloning.
Returns:

Returns the cloned value.

Type
*

(static) compact(array) → {Array}

Source:

Creates an array with all falsey values removed. The values false, null, 0, "", undefined, and NaN are falsey.

Example
_.compact([0, 1, false, 2, '', 3]);
// => [1, 2, 3]
Parameters:
Name Type Description
array Array

The array to compact.
Returns:

Returns the new array of filtered values.

Type
Array

(static) cond(pairs) → {function}

Source:

Creates a function that iterates over pairs invoking the corresponding function of the first predicate to return truthy. The predicate-function pairs are invoked with the this binding and arguments of the created function.

Example
var func = _.cond([
  [_.matches({ 'a': 1 }),           _.constant('matches A')],
  [_.conforms({ 'b': _.isNumber }), _.constant('matches B')],
  [_.constant(true),                _.constant('no match')]
]);

func({ 'a': 1, 'b': 2 });
// => 'matches A'

func({ 'a': 0, 'b': 1 });
// => 'matches B'

func({ 'a': '1', 'b': '2' });
// => 'no match'
Parameters:
Name Type Description
pairs Array

The predicate-function pairs.
Returns:

Returns the new function.

Type
function

(static) conforms(source) → {function}

Source:

Creates a function that invokes the predicate properties of source with the corresponding property values of a given object, returning true if all predicates return truthy, else false.

Example
var users = [
  { 'user': 'barney', 'age': 36 },
  { 'user': 'fred',   'age': 40 }
];

_.filter(users, _.conforms({ 'age': _.partial(_.gt, _, 38) }));
// => [{ 'user': 'fred', 'age': 40 }]
Parameters:
Name Type Description
source Object

The object of property predicates to conform to.
Returns:

Returns the new function.

Type
function

(static) constant(value) → {function}

Source:

Creates a function that returns value.

Example
var object = { 'user': 'fred' };
var getter = _.constant(object);

getter() === object;
// => true
Parameters:
Name Type Description
value *

The value to return from the new function.
Returns:

Returns the new function.

Type
function

(static) create(prototype, propertiesopt) → {Object}

Source:

Creates an object that inherits from the prototype object. If a properties object is given its own enumerable properties are assigned to the created object.

Example
function Shape() {
  this.x = 0;
  this.y = 0;
}

function Circle() {
  Shape.call(this);
}

Circle.prototype = _.create(Shape.prototype, {
  'constructor': Circle
});

var circle = new Circle;
circle instanceof Circle;
// => true

circle instanceof Shape;
// => true
Parameters:
Name Type Attributes Description
prototype Object

The object to inherit from.
properties Object <optional>

The properties to assign to the object.
Returns:

Returns the new object.

Type
Object

(static) curry(func, arityopt) → {function}

Source:

Creates a function that accepts arguments of func and either invokes func returning its result, if at least arity number of arguments have been provided, or returns a function that accepts the remaining func arguments, and so on. The arity of func may be specified if func.length is not sufficient.

The _.curry.placeholder value, which defaults to _ in monolithic builds, may be used as a placeholder for provided arguments.

Note: This method doesn't set the "length" property of curried functions.

Example
var abc = function(a, b, c) {
  return [a, b, c];
};

var curried = _.curry(abc);

curried(1)(2)(3);
// => [1, 2, 3]

curried(1, 2)(3);
// => [1, 2, 3]

curried(1, 2, 3);
// => [1, 2, 3]

// Curried with placeholders.
curried(1)(_, 3)(2);
// => [1, 2, 3]
Parameters:
Name Type Attributes Default Description
func function

The function to curry.
arity number <optional>
 func.length

The arity of func.
Returns:

Returns the new curried function.

Type
function

(static) curryRight(func, arityopt) → {function}

Source:

This method is like _.curry except that arguments are applied to func in the manner of _.partialRight instead of _.partial.

The _.curryRight.placeholder value, which defaults to _ in monolithic builds, may be used as a placeholder for provided arguments.

Note: This method doesn't set the "length" property of curried functions.

Example
var abc = function(a, b, c) {
  return [a, b, c];
};

var curried = _.curryRight(abc);

curried(3)(2)(1);
// => [1, 2, 3]

curried(2, 3)(1);
// => [1, 2, 3]

curried(1, 2, 3);
// => [1, 2, 3]

// Curried with placeholders.
curried(3)(1, _)(2);
// => [1, 2, 3]
Parameters:
Name Type Attributes Default Description
func function

The function to curry.
arity number <optional>
 func.length

The arity of func.
Returns:

Returns the new curried function.

Type
function

(static) debounce(func, waitopt, optionsopt) → {function}

Source:

Creates a debounced function that delays invoking func until after wait milliseconds have elapsed since the last time the debounced function was invoked. The debounced function comes with a cancel method to cancel delayed func invocations and a flush method to immediately invoke them. Provide an options object to indicate whether func should be invoked on the leading and/or trailing edge of the wait timeout. The func is invoked with the last arguments provided to the debounced function. Subsequent calls to the debounced function return the result of the last func invocation.

Note: If leading and trailing options are true, func is invoked on the trailing edge of the timeout only if the debounced function is invoked more than once during the wait timeout.

See David Corbacho's article for details over the differences between _.debounce and _.throttle.

Example
// Avoid costly calculations while the window size is in flux.
jQuery(window).on('resize', _.debounce(calculateLayout, 150));

// Invoke `sendMail` when clicked, debouncing subsequent calls.
jQuery(element).on('click', _.debounce(sendMail, 300, {
  'leading': true,
  'trailing': false
}));

// Ensure `batchLog` is invoked once after 1 second of debounced calls.
var debounced = _.debounce(batchLog, 250, { 'maxWait': 1000 });
var source = new EventSource('/stream');
jQuery(source).on('message', debounced);

// Cancel the trailing debounced invocation.
jQuery(window).on('popstate', debounced.cancel);
Parameters:
Name Type Attributes Default Description
func function

The function to debounce.
wait number <optional>
 0

The number of milliseconds to delay.
options Object <optional>

The options object.

Properties
Name Type Attributes Default Description
leading boolean <optional>
 false

Specify invoking on the leading edge of the timeout.
maxWait number <optional>

The maximum time func is allowed to be delayed before it's invoked.
trailing boolean <optional>
 true

Specify invoking on the trailing edge of the timeout.
Returns:

Returns the new debounced function.

Type
function

(static) deburr(stringopt) → {string}

Source:

Deburrs string by converting latin-1 supplementary letters#Character_table) to basic latin letters and removing combining diacritical marks.

Example
_.deburr('déjà vu');
// => 'deja vu'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to deburr.
Returns:

Returns the deburred string.

Type
string

(static) drop(array, nopt) → {Array}

Source:

Creates a slice of array with n elements dropped from the beginning.

Example
_.drop([1, 2, 3]);
// => [2, 3]

_.drop([1, 2, 3], 2);
// => [3]

_.drop([1, 2, 3], 5);
// => []

_.drop([1, 2, 3], 0);
// => [1, 2, 3]
Parameters:
Name Type Attributes Default Description
array Array

The array to query.
n number <optional>
 1

The number of elements to drop.
Returns:

Returns the slice of array.

Type
Array

(static) dropRight(array, nopt) → {Array}

Source:

Creates a slice of array with n elements dropped from the end.

Example
_.dropRight([1, 2, 3]);
// => [1, 2]

_.dropRight([1, 2, 3], 2);
// => [1]

_.dropRight([1, 2, 3], 5);
// => []

_.dropRight([1, 2, 3], 0);
// => [1, 2, 3]
Parameters:
Name Type Attributes Default Description
array Array

The array to query.
n number <optional>
 1

The number of elements to drop.
Returns:

Returns the slice of array.

Type
Array

(static) dropRightWhile(array, predicateopt) → {Array}

Source:

Creates a slice of array excluding elements dropped from the end. Elements are dropped until predicate returns falsey. The predicate is invoked with three arguments: (value, index, array).

Example
var users = [
  { 'user': 'barney',  'active': true },
  { 'user': 'fred',    'active': false },
  { 'user': 'pebbles', 'active': false }
];

_.dropRightWhile(users, function(o) { return !o.active; });
// => objects for ['barney']

// The `_.matches` iteratee shorthand.
_.dropRightWhile(users, { 'user': 'pebbles', 'active': false });
// => objects for ['barney', 'fred']

// The `_.matchesProperty` iteratee shorthand.
_.dropRightWhile(users, ['active', false]);
// => objects for ['barney']

// The `_.property` iteratee shorthand.
_.dropRightWhile(users, 'active');
// => objects for ['barney', 'fred', 'pebbles']
Parameters:
Name Type Attributes Default Description
array Array

The array to query.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the slice of array.

Type
Array

(static) dropWhile(array, predicateopt) → {Array}

Source:

Creates a slice of array excluding elements dropped from the beginning. Elements are dropped until predicate returns falsey. The predicate is invoked with three arguments: (value, index, array).

Example
var users = [
  { 'user': 'barney',  'active': false },
  { 'user': 'fred',    'active': false },
  { 'user': 'pebbles', 'active': true }
];

_.dropWhile(users, function(o) { return !o.active; });
// => objects for ['pebbles']

// The `_.matches` iteratee shorthand.
_.dropWhile(users, { 'user': 'barney', 'active': false });
// => objects for ['fred', 'pebbles']

// The `_.matchesProperty` iteratee shorthand.
_.dropWhile(users, ['active', false]);
// => objects for ['pebbles']

// The `_.property` iteratee shorthand.
_.dropWhile(users, 'active');
// => objects for ['barney', 'fred', 'pebbles']
Parameters:
Name Type Attributes Default Description
array Array

The array to query.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the slice of array.

Type
Array

(static) each(collection, iterateeopt) → {Array|Object}

Source:

Iterates over elements of collection invoking iteratee for each element. The iteratee is invoked with three arguments: (value, index|key, collection). Iteratee functions may exit iteration early by explicitly returning false.

Note: As with other "Collections" methods, objects with a "length" property are iterated like arrays. To avoid this behavior use _.forIn or _.forOwn for object iteration.

Example
_([1, 2]).forEach(function(value) {
  console.log(value);
});
// => logs `1` then `2`

_.forEach({ 'a': 1, 'b': 2 }, function(value, key) {
  console.log(key);
});
// => logs 'a' then 'b' (iteration order is not guaranteed)
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns collection.

Type
Array | Object

(static) eachRight(collection, iterateeopt) → {Array|Object}

Source:

This method is like _.forEach except that it iterates over elements of collection from right to left.

Example
_.forEachRight([1, 2], function(value) {
  console.log(value);
});
// => logs `2` then `1`
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns collection.

Type
Array | Object

(static) endsWith(stringopt, targetopt, positionopt) → {boolean}

Source:

Checks if string ends with the given target string.

Example
_.endsWith('abc', 'c');
// => true

_.endsWith('abc', 'b');
// => false

_.endsWith('abc', 'b', 2);
// => true
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to search.
target string <optional>

The string to search for.
position number <optional>
 string.length

The position to search from.
Returns:

Returns true if string ends with target, else false.

Type
boolean

(static) eq(value, other) → {boolean}

Source:

Performs a SameValueZero comparison between two values to determine if they are equivalent.

Example
var object = { 'user': 'fred' };
var other = { 'user': 'fred' };

_.eq(object, object);
// => true

_.eq(object, other);
// => false

_.eq('a', 'a');
// => true

_.eq('a', Object('a'));
// => false

_.eq(NaN, NaN);
// => true
Parameters:
Name Type Description
value *

The value to compare.
other *

The other value to compare.
Returns:

Returns true if the values are equivalent, else false.

Type
boolean

(static) escape(stringopt) → {string}

Source:

Converts the characters "&", "<", ">", '"', "'", and "`" in string to their corresponding HTML entities.

Note: No other characters are escaped. To escape additional characters use a third-party library like he.

Though the ">" character is escaped for symmetry, characters like ">" and "/" don't need escaping in HTML and have no special meaning unless they're part of a tag or unquoted attribute value. See Mathias Bynens's article (under "semi-related fun fact") for more details.

Backticks are escaped because in IE < 9, they can break out of attribute values or HTML comments. See #59, #102, #108, and #133 of the HTML5 Security Cheatsheet for more details.

When working with HTML you should always quote attribute values to reduce XSS vectors.

Example
_.escape('fred, barney, & pebbles');
// => 'fred, barney, &amp; pebbles'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to escape.
Returns:

Returns the escaped string.

Type
string

(static) escapeRegExp(stringopt) → {string}

Source:

Escapes the RegExp special characters "^", "$", "\", ".", "*", "+", "?", "(", ")", "[", "]", "{", "}", and "|" in string.

Example
_.escapeRegExp('[lodash](https://lodash.com/)');
// => '\[lodash\]\(https://lodash\.com/\)'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to escape.
Returns:

Returns the escaped string.

Type
string

(static) every(collection, predicateopt) → {boolean}

Source:

Checks if predicate returns truthy for all elements of collection. Iteration is stopped once predicate returns falsey. The predicate is invoked with three arguments: (value, index|key, collection).

Example
_.every([true, 1, null, 'yes'], Boolean);
// => false

var users = [
  { 'user': 'barney', 'active': false },
  { 'user': 'fred',   'active': false }
];

// The `_.matches` iteratee shorthand.
_.every(users, { 'user': 'barney', 'active': false });
// => false

// The `_.matchesProperty` iteratee shorthand.
_.every(users, ['active', false]);
// => true

// The `_.property` iteratee shorthand.
_.every(users, 'active');
// => false
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns true if all elements pass the predicate check, else false.

Type
boolean

(static) fill(array, value, startopt, endopt) → {Array}

Source:

Fills elements of array with value from start up to, but not including, end.

Note: This method mutates array.

Example
var array = [1, 2, 3];

_.fill(array, 'a');
console.log(array);
// => ['a', 'a', 'a']

_.fill(Array(3), 2);
// => [2, 2, 2]

_.fill([4, 6, 8, 10], '*', 1, 3);
// => [4, '*', '*', 10]
Parameters:
Name Type Attributes Default Description
array Array

The array to fill.
value *

The value to fill array with.
start number <optional>
 0

The start position.
end number <optional>
 array.length

The end position.
Returns:

Returns array.

Type
Array

(static) filter(collection, predicateopt) → {Array}

Source:

Iterates over elements of collection, returning an array of all elements predicate returns truthy for. The predicate is invoked with three arguments: (value, index|key, collection).

Example
var users = [
  { 'user': 'barney', 'age': 36, 'active': true },
  { 'user': 'fred',   'age': 40, 'active': false }
];

_.filter(users, function(o) { return !o.active; });
// => objects for ['fred']

// The `_.matches` iteratee shorthand.
_.filter(users, { 'age': 36, 'active': true });
// => objects for ['barney']

// The `_.matchesProperty` iteratee shorthand.
_.filter(users, ['active', false]);
// => objects for ['fred']

// The `_.property` iteratee shorthand.
_.filter(users, 'active');
// => objects for ['barney']
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the new filtered array.

Type
Array

(static) find(collection, predicateopt) → {*}

Source:

Iterates over elements of collection, returning the first element predicate returns truthy for. The predicate is invoked with three arguments: (value, index|key, collection).

Example
var users = [
  { 'user': 'barney',  'age': 36, 'active': true },
  { 'user': 'fred',    'age': 40, 'active': false },
  { 'user': 'pebbles', 'age': 1,  'active': true }
];

_.find(users, function(o) { return o.age < 40; });
// => object for 'barney'

// The `_.matches` iteratee shorthand.
_.find(users, { 'age': 1, 'active': true });
// => object for 'pebbles'

// The `_.matchesProperty` iteratee shorthand.
_.find(users, ['active', false]);
// => object for 'fred'

// The `_.property` iteratee shorthand.
_.find(users, 'active');
// => object for 'barney'
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to search.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the matched element, else undefined.

Type
*

(static) findIndex(array, predicateopt) → {number}

Source:

This method is like _.find except that it returns the index of the first element predicate returns truthy for instead of the element itself.

Example
var users = [
  { 'user': 'barney',  'active': false },
  { 'user': 'fred',    'active': false },
  { 'user': 'pebbles', 'active': true }
];

_.findIndex(users, function(o) { return o.user == 'barney'; });
// => 0

// The `_.matches` iteratee shorthand.
_.findIndex(users, { 'user': 'fred', 'active': false });
// => 1

// The `_.matchesProperty` iteratee shorthand.
_.findIndex(users, ['active', false]);
// => 0

// The `_.property` iteratee shorthand.
_.findIndex(users, 'active');
// => 2
Parameters:
Name Type Attributes Default Description
array Array

The array to search.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the index of the found element, else -1.

Type
number

(static) findKey(object, predicateopt) → {string|undefined}

Source:

This method is like _.find except that it returns the key of the first element predicate returns truthy for instead of the element itself.

Example
var users = {
  'barney':  { 'age': 36, 'active': true },
  'fred':    { 'age': 40, 'active': false },
  'pebbles': { 'age': 1,  'active': true }
};

_.findKey(users, function(o) { return o.age < 40; });
// => 'barney' (iteration order is not guaranteed)

// The `_.matches` iteratee shorthand.
_.findKey(users, { 'age': 1, 'active': true });
// => 'pebbles'

// The `_.matchesProperty` iteratee shorthand.
_.findKey(users, ['active', false]);
// => 'fred'

// The `_.property` iteratee shorthand.
_.findKey(users, 'active');
// => 'barney'
Parameters:
Name Type Attributes Default Description
object Object

The object to search.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the key of the matched element, else undefined.

Type
string | undefined

(static) findLast(collection, predicateopt) → {*}

Source:

This method is like _.find except that it iterates over elements of collection from right to left.

Example
_.findLast([1, 2, 3, 4], function(n) {
  return n % 2 == 1;
});
// => 3
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to search.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the matched element, else undefined.

Type
*

(static) findLastIndex(array, predicateopt) → {number}

Source:

This method is like _.findIndex except that it iterates over elements of collection from right to left.

Example
var users = [
  { 'user': 'barney',  'active': true },
  { 'user': 'fred',    'active': false },
  { 'user': 'pebbles', 'active': false }
];

_.findLastIndex(users, function(o) { return o.user == 'pebbles'; });
// => 2

// The `_.matches` iteratee shorthand.
_.findLastIndex(users, { 'user': 'barney', 'active': true });
// => 0

// The `_.matchesProperty` iteratee shorthand.
_.findLastIndex(users, ['active', false]);
// => 2

// The `_.property` iteratee shorthand.
_.findLastIndex(users, 'active');
// => 0
Parameters:
Name Type Attributes Default Description
array Array

The array to search.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the index of the found element, else -1.

Type
number

(static) findLastKey(object, predicateopt) → {string|undefined}

Source:

This method is like _.findKey except that it iterates over elements of a collection in the opposite order.

Example
var users = {
  'barney':  { 'age': 36, 'active': true },
  'fred':    { 'age': 40, 'active': false },
  'pebbles': { 'age': 1,  'active': true }
};

_.findLastKey(users, function(o) { return o.age < 40; });
// => returns 'pebbles' assuming `_.findKey` returns 'barney'

// The `_.matches` iteratee shorthand.
_.findLastKey(users, { 'age': 36, 'active': true });
// => 'barney'

// The `_.matchesProperty` iteratee shorthand.
_.findLastKey(users, ['active', false]);
// => 'fred'

// The `_.property` iteratee shorthand.
_.findLastKey(users, 'active');
// => 'pebbles'
Parameters:
Name Type Attributes Default Description
object Object

The object to search.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the key of the matched element, else undefined.

Type
string | undefined

(static) first(array) → {*}

Source:

Gets the first element of array.

Example
_.head([1, 2, 3]);
// => 1

_.head([]);
// => undefined
Parameters:
Name Type Description
array Array

The array to query.
Returns:

Returns the first element of array.

Type
*

(static) flatMap(collection, iterateeopt) → {Array}

Source:

Creates an array of flattened values by running each element in collection through iteratee and concating its result to the other mapped values. The iteratee is invoked with three arguments: (value, index|key, collection).

Example
function duplicate(n) {
  return [n, n];
}

_.flatMap([1, 2], duplicate);
// => [1, 1, 2, 2]
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
iteratee function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the new flattened array.

Type
Array

(static) flatten(array) → {Array}

Source:

Flattens array a single level deep.

Example
_.flatten([1, [2, [3, [4]], 5]]);
// => [1, 2, [3, [4]], 5]
Parameters:
Name Type Description
array Array

The array to flatten.
Returns:

Returns the new flattened array.

Type
Array

(static) flattenDeep(array) → {Array}

Source:

Recursively flattens array.

Example
_.flattenDeep([1, [2, [3, [4]], 5]]);
// => [1, 2, 3, 4, 5]
Parameters:
Name Type Description
array Array

The array to flatten.
Returns:

Returns the new flattened array.

Type
Array

(static) flattenDepth(array, depthopt) → {Array}

Source:

Recursively flatten array up to depth times.

Example
var array = [1, [2, [3, [4]], 5]];

_.flattenDepth(array, 1);
// => [1, 2, [3, [4]], 5]

_.flattenDepth(array, 2);
// => [1, 2, 3, [4], 5]
Parameters:
Name Type Attributes Default Description
array Array

The array to flatten.
depth number <optional>
 1

The maximum recursion depth.
Returns:

Returns the new flattened array.

Type
Array

(static) flip(func) → {function}

Source:

Creates a function that invokes func with arguments reversed.

Example
var flipped = _.flip(function() {
  return _.toArray(arguments);
});

flipped('a', 'b', 'c', 'd');
// => ['d', 'c', 'b', 'a']
Parameters:
Name Type Description
func function

The function to flip arguments for.
Returns:

Returns the new function.

Type
function

(static) forIn(object, iterateeopt) → {Object}

Source:

Iterates over own and inherited enumerable properties of an object invoking iteratee for each property. The iteratee is invoked with three arguments: (value, key, object). Iteratee functions may exit iteration early by explicitly returning false.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.forIn(new Foo, function(value, key) {
  console.log(key);
});
// => logs 'a', 'b', then 'c' (iteration order is not guaranteed)
Parameters:
Name Type Attributes Default Description
object Object

The object to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns object.

Type
Object

(static) forInRight(object, iterateeopt) → {Object}

Source:

This method is like _.forIn except that it iterates over properties of object in the opposite order.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.forInRight(new Foo, function(value, key) {
  console.log(key);
});
// => logs 'c', 'b', then 'a' assuming `_.forIn` logs 'a', 'b', then 'c'
Parameters:
Name Type Attributes Default Description
object Object

The object to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns object.

Type
Object

(static) forOwn(object, iterateeopt) → {Object}

Source:

Iterates over own enumerable properties of an object invoking iteratee for each property. The iteratee is invoked with three arguments: (value, key, object). Iteratee functions may exit iteration early by explicitly returning false.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.forOwn(new Foo, function(value, key) {
  console.log(key);
});
// => logs 'a' then 'b' (iteration order is not guaranteed)
Parameters:
Name Type Attributes Default Description
object Object

The object to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns object.

Type
Object

(static) forOwnRight(object, iterateeopt) → {Object}

Source:

This method is like _.forOwn except that it iterates over properties of object in the opposite order.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.forOwnRight(new Foo, function(value, key) {
  console.log(key);
});
// => logs 'b' then 'a' assuming `_.forOwn` logs 'a' then 'b'
Parameters:
Name Type Attributes Default Description
object Object

The object to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns object.

Type
Object

(static) fromPairs(pairs) → {Object}

Source:

The inverse of _.toPairs; this method returns an object composed from key-value pairs.

Example
_.fromPairs([['fred', 30], ['barney', 40]]);
// => { 'fred': 30, 'barney': 40 }
Parameters:
Name Type Description
pairs Array

The key-value pairs.
Returns:

Returns the new object.

Type
Object

(static) functions(object) → {Array}

Source:

Creates an array of function property names from own enumerable properties of object.

Example
function Foo() {
  this.a = _.constant('a');
  this.b = _.constant('b');
}

Foo.prototype.c = _.constant('c');

_.functions(new Foo);
// => ['a', 'b']
Parameters:
Name Type Description
object Object

The object to inspect.
Returns:

Returns the new array of property names.

Type
Array

(static) functionsIn(object) → {Array}

Source:

Creates an array of function property names from own and inherited enumerable properties of object.

Example
function Foo() {
  this.a = _.constant('a');
  this.b = _.constant('b');
}

Foo.prototype.c = _.constant('c');

_.functionsIn(new Foo);
// => ['a', 'b', 'c']
Parameters:
Name Type Description
object Object

The object to inspect.
Returns:

Returns the new array of property names.

Type
Array

(static) get(object, path, defaultValueopt) → {*}

Source:

Gets the value at path of object. If the resolved value is undefined the defaultValue is used in its place.

Example
var object = { 'a': [{ 'b': { 'c': 3 } }] };

_.get(object, 'a[0].b.c');
// => 3

_.get(object, ['a', '0', 'b', 'c']);
// => 3

_.get(object, 'a.b.c', 'default');
// => 'default'
Parameters:
Name Type Attributes Description
object Object

The object to query.
path Array | string

The path of the property to get.
defaultValue * <optional>

The value returned if the resolved value is undefined.
Returns:

Returns the resolved value.

Type
*

(static) gt(value, other) → {boolean}

Source:

Checks if value is greater than other.

Example
_.gt(3, 1);
// => true

_.gt(3, 3);
// => false

_.gt(1, 3);
// => false
Parameters:
Name Type Description
value *

The value to compare.
other *

The other value to compare.
Returns:

Returns true if value is greater than other, else false.

Type
boolean

(static) gte(value, other) → {boolean}

Source:

Checks if value is greater than or equal to other.

Example
_.gte(3, 1);
// => true

_.gte(3, 3);
// => true

_.gte(1, 3);
// => false
Parameters:
Name Type Description
value *

The value to compare.
other *

The other value to compare.
Returns:

Returns true if value is greater than or equal to other, else false.

Type
boolean

(static) has(object, path) → {boolean}

Source:

Checks if path is a direct property of object.

Example
var object = { 'a': { 'b': { 'c': 3 } } };
var other = _.create({ 'a': _.create({ 'b': _.create({ 'c': 3 }) }) });

_.has(object, 'a');
// => true

_.has(object, 'a.b.c');
// => true

_.has(object, ['a', 'b', 'c']);
// => true

_.has(other, 'a');
// => false
Parameters:
Name Type Description
object Object

The object to query.
path Array | string

The path to check.
Returns:

Returns true if path exists, else false.

Type
boolean

(static) hasIn(object, path) → {boolean}

Source:

Checks if path is a direct or inherited property of object.

Example
var object = _.create({ 'a': _.create({ 'b': _.create({ 'c': 3 }) }) });

_.hasIn(object, 'a');
// => true

_.hasIn(object, 'a.b.c');
// => true

_.hasIn(object, ['a', 'b', 'c']);
// => true

_.hasIn(object, 'b');
// => false
Parameters:
Name Type Description
object Object

The object to query.
path Array | string

The path to check.
Returns:

Returns true if path exists, else false.

Type
boolean

(static) identity(value) → {*}

Source:

This method returns the first argument given to it.

Example
var object = { 'user': 'fred' };

_.identity(object) === object;
// => true
Parameters:
Name Type Description
value *

Any value.
Returns:

Returns value.

Type
*

(static) includes(collection, value, fromIndexopt) → {boolean}

Source:

Checks if value is in collection. If collection is a string it's checked for a substring of value, otherwise SameValueZero is used for equality comparisons. If fromIndex is negative, it's used as the offset from the end of collection.

Example
_.includes([1, 2, 3], 1);
// => true

_.includes([1, 2, 3], 1, 2);
// => false

_.includes({ 'user': 'fred', 'age': 40 }, 'fred');
// => true

_.includes('pebbles', 'eb');
// => true
Parameters:
Name Type Attributes Default Description
collection Array | Object | string

The collection to search.
value *

The value to search for.
fromIndex number <optional>
 0

The index to search from.
Returns:

Returns true if value is found, else false.

Type
boolean

(static) indexOf(array, value, fromIndexopt) → {number}

Source:

Gets the index at which the first occurrence of value is found in array using SameValueZero for equality comparisons. If fromIndex is negative, it's used as the offset from the end of array.

Example
_.indexOf([1, 2, 1, 2], 2);
// => 1

// Search from the `fromIndex`.
_.indexOf([1, 2, 1, 2], 2, 2);
// => 3
Parameters:
Name Type Attributes Default Description
array Array

The array to search.
value *

The value to search for.
fromIndex number <optional>
 0

The index to search from.
Returns:

Returns the index of the matched value, else -1.

Type
number

(static) initial(array) → {Array}

Source:

Gets all but the last element of array.

Example
_.initial([1, 2, 3]);
// => [1, 2]
Parameters:
Name Type Description
array Array

The array to query.
Returns:

Returns the slice of array.

Type
Array

(static) inRange(number, startopt, end) → {boolean}

Source:

Checks if n is between start and up to but not including, end. If end is not specified it's set to start with start then set to 0. If start is greater than end the params are swapped to support negative ranges.

Example
_.inRange(3, 2, 4);
// => true

_.inRange(4, 8);
// => true

_.inRange(4, 2);
// => false

_.inRange(2, 2);
// => false

_.inRange(1.2, 2);
// => true

_.inRange(5.2, 4);
// => false

_.inRange(-3, -2, -6);
// => true
Parameters:
Name Type Attributes Default Description
number number

The number to check.
start number <optional>
 0

The start of the range.
end number

The end of the range.
Returns:

Returns true if number is in the range, else false.

Type
boolean

(static) isArguments(value) → {boolean}

Source:

Checks if value is likely an arguments object.

Example
_.isArguments(function() { return arguments; }());
// => true

_.isArguments([1, 2, 3]);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isArrayBuffer(value) → {boolean}

Source:

Checks if value is classified as an ArrayBuffer object.

Example
_.isArrayBuffer(new ArrayBuffer(2));
// => true

_.isArrayBuffer(new Array(2));
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isArrayLike(value) → {boolean}

Source:

Checks if value is array-like. A value is considered array-like if it's not a function and has a value.length that's an integer greater than or equal to 0 and less than or equal to Number.MAX_SAFE_INTEGER.

Example
_.isArrayLike([1, 2, 3]);
// => true

_.isArrayLike(document.body.children);
// => true

_.isArrayLike('abc');
// => true

_.isArrayLike(_.noop);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is array-like, else false.

Type
boolean

(static) isArrayLikeObject(value) → {boolean}

Source:

This method is like _.isArrayLike except that it also checks if value is an object.

Example
_.isArrayLikeObject([1, 2, 3]);
// => true

_.isArrayLikeObject(document.body.children);
// => true

_.isArrayLikeObject('abc');
// => false

_.isArrayLikeObject(_.noop);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is an array-like object, else false.

Type
boolean

(static) isBoolean(value) → {boolean}

Source:

Checks if value is classified as a boolean primitive or object.

Example
_.isBoolean(false);
// => true

_.isBoolean(null);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isDate(value) → {boolean}

Source:

Checks if value is classified as a Date object.

Example
_.isDate(new Date);
// => true

_.isDate('Mon April 23 2012');
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isElement(value) → {boolean}

Source:

Checks if value is likely a DOM element.

Example
_.isElement(document.body);
// => true

_.isElement('<body>');
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is a DOM element, else false.

Type
boolean

(static) isEmpty(value) → {boolean}

Source:

Checks if value is empty. A value is considered empty unless it's an arguments object, array, string, or jQuery-like collection with a length greater than 0 or an object with own enumerable properties.

Example
_.isEmpty(null);
// => true

_.isEmpty(true);
// => true

_.isEmpty(1);
// => true

_.isEmpty([1, 2, 3]);
// => false

_.isEmpty({ 'a': 1 });
// => false
Parameters:
Name Type Description
value Array | Object | string

The value to inspect.
Returns:

Returns true if value is empty, else false.

Type
boolean

(static) isEqual(value, other) → {boolean}

Source:

Performs a deep comparison between two values to determine if they are equivalent.

Note: This method supports comparing arrays, array buffers, booleans, date objects, error objects, maps, numbers, Object objects, regexes, sets, strings, symbols, and typed arrays. Object objects are compared by their own, not inherited, enumerable properties. Functions and DOM nodes are not supported.

Example
var object = { 'user': 'fred' };
var other = { 'user': 'fred' };

_.isEqual(object, other);
// => true

object === other;
// => false
Parameters:
Name Type Description
value *

The value to compare.
other *

The other value to compare.
Returns:

Returns true if the values are equivalent, else false.

Type
boolean

(static) isEqualWith(value, other, customizeropt) → {boolean}

Source:

This method is like _.isEqual except that it accepts customizer which is invoked to compare values. If customizer returns undefined comparisons are handled by the method instead. The customizer is invoked with up to six arguments: (objValue, othValue [, index|key, object, other, stack]).

Example
function isGreeting(value) {
  return /^h(?:i|ello)$/.test(value);
}

function customizer(objValue, othValue) {
  if (isGreeting(objValue) && isGreeting(othValue)) {
    return true;
  }
}

var array = ['hello', 'goodbye'];
var other = ['hi', 'goodbye'];

_.isEqualWith(array, other, customizer);
// => true
Parameters:
Name Type Attributes Description
value *

The value to compare.
other *

The other value to compare.
customizer function <optional>

The function to customize comparisons.
Returns:

Returns true if the values are equivalent, else false.

Type
boolean

(static) isError(value) → {boolean}

Source:

Checks if value is an Error, EvalError, RangeError, ReferenceError, SyntaxError, TypeError, or URIError object.

Example
_.isError(new Error);
// => true

_.isError(Error);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is an error object, else false.

Type
boolean

(static) isFinite(value) → {boolean}

Source:

Checks if value is a finite primitive number.

Note: This method is based on Number.isFinite.

Example
_.isFinite(3);
// => true

_.isFinite(Number.MAX_VALUE);
// => true

_.isFinite(3.14);
// => true

_.isFinite(Infinity);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is a finite number, else false.

Type
boolean

(static) isFunction(value) → {boolean}

Source:

Checks if value is classified as a Function object.

Example
_.isFunction(_);
// => true

_.isFunction(/abc/);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isInteger(value) → {boolean}

Source:

Checks if value is an integer.

Note: This method is based on Number.isInteger.

Example
_.isInteger(3);
// => true

_.isInteger(Number.MIN_VALUE);
// => false

_.isInteger(Infinity);
// => false

_.isInteger('3');
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is an integer, else false.

Type
boolean

(static) isLength(value) → {boolean}

Source:

Checks if value is a valid array-like length.

Note: This function is loosely based on ToLength.

Example
_.isLength(3);
// => true

_.isLength(Number.MIN_VALUE);
// => false

_.isLength(Infinity);
// => false

_.isLength('3');
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is a valid length, else false.

Type
boolean

(static) isMap(value) → {boolean}

Source:

Checks if value is classified as a Map object.

Example
_.isMap(new Map);
// => true

_.isMap(new WeakMap);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isMatch(object, source) → {boolean}

Source:

Performs a partial deep comparison between object and source to determine if object contains equivalent property values. This method is equivalent to a _.matches function when source is partially applied.

Note: This method supports comparing the same values as _.isEqual.

Example
var object = { 'user': 'fred', 'age': 40 };

_.isMatch(object, { 'age': 40 });
// => true

_.isMatch(object, { 'age': 36 });
// => false
Parameters:
Name Type Description
object Object

The object to inspect.
source Object

The object of property values to match.
Returns:

Returns true if object is a match, else false.

Type
boolean

(static) isMatchWith(object, source, customizeropt) → {boolean}

Source:

This method is like _.isMatch except that it accepts customizer which is invoked to compare values. If customizer returns undefined comparisons are handled by the method instead. The customizer is invoked with five arguments: (objValue, srcValue, index|key, object, source).

Example
function isGreeting(value) {
  return /^h(?:i|ello)$/.test(value);
}

function customizer(objValue, srcValue) {
  if (isGreeting(objValue) && isGreeting(srcValue)) {
    return true;
  }
}

var object = { 'greeting': 'hello' };
var source = { 'greeting': 'hi' };

_.isMatchWith(object, source, customizer);
// => true
Parameters:
Name Type Attributes Description
object Object

The object to inspect.
source Object

The object of property values to match.
customizer function <optional>

The function to customize comparisons.
Returns:

Returns true if object is a match, else false.

Type
boolean

(static) isNaN(value) → {boolean}

Source:

Checks if value is NaN.

Note: This method is not the same as isNaN which returns true for undefined and other non-numeric values.

Example
_.isNaN(NaN);
// => true

_.isNaN(new Number(NaN));
// => true

isNaN(undefined);
// => true

_.isNaN(undefined);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is NaN, else false.

Type
boolean

(static) isNative(value) → {boolean}

Source:

Checks if value is a native function.

Example
_.isNative(Array.prototype.push);
// => true

_.isNative(_);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is a native function, else false.

Type
boolean

(static) isNil(value) → {boolean}

Source:

Checks if value is null or undefined.

Example
_.isNil(null);
// => true

_.isNil(void 0);
// => true

_.isNil(NaN);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is nullish, else false.

Type
boolean

(static) isNull(value) → {boolean}

Source:

Checks if value is null.

Example
_.isNull(null);
// => true

_.isNull(void 0);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is null, else false.

Type
boolean

(static) isNumber(value) → {boolean}

Source:

Checks if value is classified as a Number primitive or object.

Note: To exclude Infinity, -Infinity, and NaN, which are classified as numbers, use the _.isFinite method.

Example
_.isNumber(3);
// => true

_.isNumber(Number.MIN_VALUE);
// => true

_.isNumber(Infinity);
// => true

_.isNumber('3');
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isObject(value) → {boolean}

Source:

Checks if value is the language type of Object. (e.g. arrays, functions, objects, regexes, new Number(0), and new String(''))

Example
_.isObject({});
// => true

_.isObject([1, 2, 3]);
// => true

_.isObject(_.noop);
// => true

_.isObject(null);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is an object, else false.

Type
boolean

(static) isObjectLike(value) → {boolean}

Source:

Checks if value is object-like. A value is object-like if it's not null and has a typeof result of "object".

Example
_.isObjectLike({});
// => true

_.isObjectLike([1, 2, 3]);
// => true

_.isObjectLike(_.noop);
// => false

_.isObjectLike(null);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is object-like, else false.

Type
boolean

(static) isPlainObject(value) → {boolean}

Source:

Checks if value is a plain object, that is, an object created by the Object constructor or one with a [[Prototype]] of null.

Example
function Foo() {
  this.a = 1;
}

_.isPlainObject(new Foo);
// => false

_.isPlainObject([1, 2, 3]);
// => false

_.isPlainObject({ 'x': 0, 'y': 0 });
// => true

_.isPlainObject(Object.create(null));
// => true
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is a plain object, else false.

Type
boolean

(static) isRegExp(value) → {boolean}

Source:

Checks if value is classified as a RegExp object.

Example
_.isRegExp(/abc/);
// => true

_.isRegExp('/abc/');
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isSafeInteger(value) → {boolean}

Source:

Checks if value is a safe integer. An integer is safe if it's an IEEE-754 double precision number which isn't the result of a rounded unsafe integer.

Note: This method is based on Number.isSafeInteger.

Example
_.isSafeInteger(3);
// => true

_.isSafeInteger(Number.MIN_VALUE);
// => false

_.isSafeInteger(Infinity);
// => false

_.isSafeInteger('3');
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is a safe integer, else false.

Type
boolean

(static) isSet(value) → {boolean}

Source:

Checks if value is classified as a Set object.

Example
_.isSet(new Set);
// => true

_.isSet(new WeakSet);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isString(value) → {boolean}

Source:

Checks if value is classified as a String primitive or object.

Example
_.isString('abc');
// => true

_.isString(1);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isSymbol(value) → {boolean}

Source:

Checks if value is classified as a Symbol primitive or object.

Example
_.isSymbol(Symbol.iterator);
// => true

_.isSymbol('abc');
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isTypedArray(value) → {boolean}

Source:

Checks if value is classified as a typed array.

Example
_.isTypedArray(new Uint8Array);
// => true

_.isTypedArray([]);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isUndefined(value) → {boolean}

Source:

Checks if value is undefined.

Example
_.isUndefined(void 0);
// => true

_.isUndefined(null);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is undefined, else false.

Type
boolean

(static) isWeakMap(value) → {boolean}

Source:

Checks if value is classified as a WeakMap object.

Example
_.isWeakMap(new WeakMap);
// => true

_.isWeakMap(new Map);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) isWeakSet(value) → {boolean}

Source:

Checks if value is classified as a WeakSet object.

Example
_.isWeakSet(new WeakSet);
// => true

_.isWeakSet(new Set);
// => false
Parameters:
Name Type Description
value *

The value to check.
Returns:

Returns true if value is correctly classified, else false.

Type
boolean

(static) iteratee(funcopt) → {function}

Source:

Creates a function that invokes func with the arguments of the created function. If func is a property name the created callback returns the property value for a given element. If func is an object the created callback returns true for elements that contain the equivalent object properties, otherwise it returns false.

Example
var users = [
  { 'user': 'barney', 'age': 36 },
  { 'user': 'fred',   'age': 40 }
];

// Create custom iteratee shorthands.
_.iteratee = _.wrap(_.iteratee, function(callback, func) {
  var p = /^(\S+)\s*([<>])\s*(\S+)$/.exec(func);
  return !p ? callback(func) : function(object) {
    return (p[2] == '>' ? object[p[1]] > p[3] : object[p[1]] < p[3]);
  };
});

_.filter(users, 'age > 36');
// => [{ 'user': 'fred', 'age': 40 }]
Parameters:
Name Type Attributes Default Description
func * <optional>
 _.identity

The value to convert to a callback.
Returns:

Returns the callback.

Type
function

(static) join(array, separatoropt) → {string}

Source:

Converts all elements in array into a string separated by separator.

Example
_.join(['a', 'b', 'c'], '~');
// => 'a~b~c'
Parameters:
Name Type Attributes Default Description
array Array

The array to convert.
separator string <optional>
 ','

The element separator.
Returns:

Returns the joined string.

Type
string

(static) keys(object) → {Array}

Source:

Creates an array of the own enumerable property names of object.

Note: Non-object values are coerced to objects. See the ES spec for more details.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.keys(new Foo);
// => ['a', 'b'] (iteration order is not guaranteed)

_.keys('hi');
// => ['0', '1']
Parameters:
Name Type Description
object Object

The object to query.
Returns:

Returns the array of property names.

Type
Array

(static) keysIn(object) → {Array}

Source:

Creates an array of the own and inherited enumerable property names of object.

Note: Non-object values are coerced to objects.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.keysIn(new Foo);
// => ['a', 'b', 'c'] (iteration order is not guaranteed)
Parameters:
Name Type Description
object Object

The object to query.
Returns:

Returns the array of property names.

Type
Array

(static) last(array) → {*}

Source:

Gets the last element of array.

Example
_.last([1, 2, 3]);
// => 3
Parameters:
Name Type Description
array Array

The array to query.
Returns:

Returns the last element of array.

Type
*

(static) lastIndexOf(array, value, fromIndexopt) → {number}

Source:

This method is like _.indexOf except that it iterates over elements of array from right to left.

Example
_.lastIndexOf([1, 2, 1, 2], 2);
// => 3

// Search from the `fromIndex`.
_.lastIndexOf([1, 2, 1, 2], 2, 2);
// => 1
Parameters:
Name Type Attributes Default Description
array Array

The array to search.
value *

The value to search for.
fromIndex number <optional>
 array.length-1

The index to search from.
Returns:

Returns the index of the matched value, else -1.

Type
number

(static) lt(value, other) → {boolean}

Source:

Checks if value is less than other.

Example
_.lt(1, 3);
// => true

_.lt(3, 3);
// => false

_.lt(3, 1);
// => false
Parameters:
Name Type Description
value *

The value to compare.
other *

The other value to compare.
Returns:

Returns true if value is less than other, else false.

Type
boolean

(static) lte(value, other) → {boolean}

Source:

Checks if value is less than or equal to other.

Example
_.lte(1, 3);
// => true

_.lte(3, 3);
// => true

_.lte(3, 1);
// => false
Parameters:
Name Type Description
value *

The value to compare.
other *

The other value to compare.
Returns:

Returns true if value is less than or equal to other, else false.

Type
boolean

(static) map(collection, iterateeopt) → {Array}

Source:

Creates an array of values by running each element in collection through iteratee. The iteratee is invoked with three arguments: (value, index|key, collection).

Many lodash methods are guarded to work as iteratees for methods like _.every, _.filter, _.map, _.mapValues, _.reject, and _.some.

The guarded methods are: ary, curry, curryRight, drop, dropRight, every, fill, invert, parseInt, random, range, rangeRight, slice, some, sortBy, take, takeRight, template, trim, trimEnd, trimStart, and words

Example
function square(n) {
  return n * n;
}

_.map([4, 8], square);
// => [16, 64]

_.map({ 'a': 4, 'b': 8 }, square);
// => [16, 64] (iteration order is not guaranteed)

var users = [
  { 'user': 'barney' },
  { 'user': 'fred' }
];

// The `_.property` iteratee shorthand.
_.map(users, 'user');
// => ['barney', 'fred']
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
iteratee function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the new mapped array.

Type
Array

(static) mapKeys(object, iterateeopt) → {Object}

Source:

The opposite of _.mapValues; this method creates an object with the same values as object and keys generated by running each own enumerable property of object through iteratee. The iteratee is invoked with three arguments: (value, key, object).

Example
_.mapKeys({ 'a': 1, 'b': 2 }, function(value, key) {
  return key + value;
});
// => { 'a1': 1, 'b2': 2 }
Parameters:
Name Type Attributes Default Description
object Object

The object to iterate over.
iteratee function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the new mapped object.

Type
Object

(static) mapValues(object, iterateeopt) → {Object}

Source:

Creates an object with the same keys as object and values generated by running each own enumerable property of object through iteratee. The iteratee is invoked with three arguments: (value, key, object).

Example
var users = {
  'fred':    { 'user': 'fred',    'age': 40 },
  'pebbles': { 'user': 'pebbles', 'age': 1 }
};

_.mapValues(users, function(o) { return o.age; });
// => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)

// The `_.property` iteratee shorthand.
_.mapValues(users, 'age');
// => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
Parameters:
Name Type Attributes Default Description
object Object

The object to iterate over.
iteratee function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the new mapped object.

Type
Object

(static) matches(source) → {function}

Source:

Creates a function that performs a partial deep comparison between a given object and source, returning true if the given object has equivalent property values, else false. The created function is equivalent to _.isMatch with a source partially applied.

Note: This method supports comparing the same values as _.isEqual.

Example
var users = [
  { 'user': 'barney', 'age': 36, 'active': true },
  { 'user': 'fred',   'age': 40, 'active': false }
];

_.filter(users, _.matches({ 'age': 40, 'active': false }));
// => [{ 'user': 'fred', 'age': 40, 'active': false }]
Parameters:
Name Type Description
source Object

The object of property values to match.
Returns:

Returns the new function.

Type
function

(static) matchesProperty(path, srcValue) → {function}

Source:

Creates a function that performs a partial deep comparison between the value at path of a given object to srcValue, returning true if the object value is equivalent, else false.

Note: This method supports comparing the same values as _.isEqual.

Example
var users = [
  { 'user': 'barney' },
  { 'user': 'fred' }
];

_.find(users, _.matchesProperty('user', 'fred'));
// => { 'user': 'fred' }
Parameters:
Name Type Description
path Array | string

The path of the property to get.
srcValue *

The value to match.
Returns:

Returns the new function.

Type
function

(static) max(array) → {*}

Source:

Computes the maximum value of array. If array is empty or falsey undefined is returned.

Example
_.max([4, 2, 8, 6]);
// => 8

_.max([]);
// => undefined
Parameters:
Name Type Description
array Array

The array to iterate over.
Returns:

Returns the maximum value.

Type
*

(static) maxBy(array, iterateeopt) → {*}

Source:

This method is like _.max except that it accepts iteratee which is invoked for each element in array to generate the criterion by which the value is ranked. The iteratee is invoked with one argument: (value).

Example
var objects = [{ 'n': 1 }, { 'n': 2 }];

_.maxBy(objects, function(o) { return o.n; });
// => { 'n': 2 }

// The `_.property` iteratee shorthand.
_.maxBy(objects, 'n');
// => { 'n': 2 }
Parameters:
Name Type Attributes Default Description
array Array

The array to iterate over.
iteratee function | Object | string <optional>
 _.identity

The iteratee invoked per element.
Returns:

Returns the maximum value.

Type
*

(static) mean(array) → {number}

Source:

Computes the mean of the values in array.

Example
_.mean([4, 2, 8, 6]);
// => 5
Parameters:
Name Type Description
array Array

The array to iterate over.
Returns:

Returns the mean.

Type
number

(static) memoize(func, resolveropt) → {function}

Source:

Creates a function that memoizes the result of func. If resolver is provided it determines the cache key for storing the result based on the arguments provided to the memoized function. By default, the first argument provided to the memoized function is used as the map cache key. The func is invoked with the this binding of the memoized function.

Note: The cache is exposed as the cache property on the memoized function. Its creation may be customized by replacing the _.memoize.Cache constructor with one whose instances implement the Map method interface of delete, get, has, and set.

Example
var object = { 'a': 1, 'b': 2 };
var other = { 'c': 3, 'd': 4 };

var values = _.memoize(_.values);
values(object);
// => [1, 2]

values(other);
// => [3, 4]

object.a = 2;
values(object);
// => [1, 2]

// Modify the result cache.
values.cache.set(object, ['a', 'b']);
values(object);
// => ['a', 'b']

// Replace `_.memoize.Cache`.
_.memoize.Cache = WeakMap;
Parameters:
Name Type Attributes Description
func function

The function to have its output memoized.
resolver function <optional>

The function to resolve the cache key.
Returns:

Returns the new memoizing function.

Type
function

(static) min(array) → {*}

Source:

Computes the minimum value of array. If array is empty or falsey undefined is returned.

Example
_.min([4, 2, 8, 6]);
// => 2

_.min([]);
// => undefined
Parameters:
Name Type Description
array Array

The array to iterate over.
Returns:

Returns the minimum value.

Type
*

(static) minBy(array, iterateeopt) → {*}

Source:

This method is like _.min except that it accepts iteratee which is invoked for each element in array to generate the criterion by which the value is ranked. The iteratee is invoked with one argument: (value).

Example
var objects = [{ 'n': 1 }, { 'n': 2 }];

_.minBy(objects, function(o) { return o.n; });
// => { 'n': 1 }

// The `_.property` iteratee shorthand.
_.minBy(objects, 'n');
// => { 'n': 1 }
Parameters:
Name Type Attributes Default Description
array Array

The array to iterate over.
iteratee function | Object | string <optional>
 _.identity

The iteratee invoked per element.
Returns:

Returns the minimum value.

Type
*

(static) mixin(objectopt, source, optionsopt) → {function|Object}

Source:

Adds all own enumerable function properties of a source object to the destination object. If object is a function then methods are added to its prototype as well.

Note: Use _.runInContext to create a pristine lodash function to avoid conflicts caused by modifying the original.

Example
function vowels(string) {
  return _.filter(string, function(v) {
    return /[aeiou]/i.test(v);
  });
}

_.mixin({ 'vowels': vowels });
_.vowels('fred');
// => ['e']

_('fred').vowels().value();
// => ['e']

_.mixin({ 'vowels': vowels }, { 'chain': false });
_('fred').vowels();
// => ['e']
Parameters:
Name Type Attributes Default Description
object function | Object <optional>
 lodash

The destination object.
source Object

The object of functions to add.
options Object <optional>

The options object.

Properties
Name Type Attributes Default Description
chain boolean <optional>
 true

Specify whether the functions added are chainable.
Returns:

Returns object.

Type
function | Object

(static) negate(predicate) → {function}

Source:

Creates a function that negates the result of the predicate func. The func predicate is invoked with the this binding and arguments of the created function.

Example
function isEven(n) {
  return n % 2 == 0;
}

_.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
// => [1, 3, 5]
Parameters:
Name Type Description
predicate function

The predicate to negate.
Returns:

Returns the new function.

Type
function

(static) noConflict() → {function}

Source:

Reverts the _ variable to its previous value and returns a reference to the lodash function.

Example
var lodash = _.noConflict();
Returns:

Returns the lodash function.

Type
function

(static) noop()

Source:

A no-operation function that returns undefined regardless of the arguments it receives.

Example
var object = { 'user': 'fred' };

_.noop(object) === undefined;
// => true

(static) nthArg(nopt) → {function}

Source:

Creates a function that returns its nth argument.

Example
var func = _.nthArg(1);

func('a', 'b', 'c');
// => 'b'
Parameters:
Name Type Attributes Default Description
n number <optional>
 0

The index of the argument to return.
Returns:

Returns the new function.

Type
function

(static) omitBy(object, predicateopt) → {Object}

Source:

The opposite of _.pickBy; this method creates an object composed of the own and inherited enumerable properties of object that predicate doesn't return truthy for. The predicate is invoked with two arguments: (value, key).

Example
var object = { 'a': 1, 'b': '2', 'c': 3 };

_.omitBy(object, _.isNumber);
// => { 'b': '2' }
Parameters:
Name Type Attributes Default Description
object Object

The source object.
predicate function | Object | string <optional>
 _.identity

The function invoked per property.
Returns:

Returns the new object.

Type
Object

(static) once(func) → {function}

Source:

Creates a function that is restricted to invoking func once. Repeat calls to the function return the value of the first invocation. The func is invoked with the this binding and arguments of the created function.

Example
var initialize = _.once(createApplication);
initialize();
initialize();
// `initialize` invokes `createApplication` once
Parameters:
Name Type Description
func function

The function to restrict.
Returns:

Returns the new restricted function.

Type
function

(static) orderBy(collection, iterateesopt, ordersopt) → {Array}

Source:

This method is like _.sortBy except that it allows specifying the sort orders of the iteratees to sort by. If orders is unspecified, all values are sorted in ascending order. Otherwise, specify an order of "desc" for descending or "asc" for ascending sort order of corresponding values.

Example
var users = [
  { 'user': 'fred',   'age': 48 },
  { 'user': 'barney', 'age': 34 },
  { 'user': 'fred',   'age': 42 },
  { 'user': 'barney', 'age': 36 }
];

// Sort by `user` in ascending order and by `age` in descending order.
_.orderBy(users, ['user', 'age'], ['asc', 'desc']);
// => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
iteratees Array.<function()> | Array.<Object> | Array.<string> <optional>
 [_.identity]

The iteratees to sort by.
orders Array.<string> <optional>

The sort orders of iteratees.
Returns:

Returns the new sorted array.

Type
Array

(static) pad(stringopt, lengthopt, charsopt) → {string}

Source:

Pads string on the left and right sides if it's shorter than length. Padding characters are truncated if they can't be evenly divided by length.

Example
_.pad('abc', 8);
// => '  abc   '

_.pad('abc', 8, '_-');
// => '_-abc_-_'

_.pad('abc', 3);
// => 'abc'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to pad.
length number <optional>
 0

The padding length.
chars string <optional>
 ' '

The string used as padding.
Returns:

Returns the padded string.

Type
string

(static) padEnd(stringopt, lengthopt, charsopt) → {string}

Source:

Pads string on the right side if it's shorter than length. Padding characters are truncated if they exceed length.

Example
_.padEnd('abc', 6);
// => 'abc   '

_.padEnd('abc', 6, '_-');
// => 'abc_-_'

_.padEnd('abc', 3);
// => 'abc'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to pad.
length number <optional>
 0

The padding length.
chars string <optional>
 ' '

The string used as padding.
Returns:

Returns the padded string.

Type
string

(static) padStart(stringopt, lengthopt, charsopt) → {string}

Source:

Pads string on the left side if it's shorter than length. Padding characters are truncated if they exceed length.

Example
_.padStart('abc', 6);
// => '   abc'

_.padStart('abc', 6, '_-');
// => '_-_abc'

_.padStart('abc', 3);
// => 'abc'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to pad.
length number <optional>
 0

The padding length.
chars string <optional>
 ' '

The string used as padding.
Returns:

Returns the padded string.

Type
string

(static) parseInt(string, radixopt) → {number}

Source:

Converts string to an integer of the specified radix. If radix is undefined or 0, a radix of 10 is used unless value is a hexadecimal, in which case a radix of 16 is used.

Note: This method aligns with the ES5 implementation of parseInt.

Example
_.parseInt('08');
// => 8

_.map(['6', '08', '10'], _.parseInt);
// => [6, 8, 10]
Parameters:
Name Type Attributes Default Description
string string

The string to convert.
radix number <optional>
 10

The radix to interpret value by.
Returns:

Returns the converted integer.

Type
number

(static) pickBy(object, predicateopt) → {Object}

Source:

Creates an object composed of the object properties predicate returns truthy for. The predicate is invoked with two arguments: (value, key).

Example
var object = { 'a': 1, 'b': '2', 'c': 3 };

_.pickBy(object, _.isNumber);
// => { 'a': 1, 'c': 3 }
Parameters:
Name Type Attributes Default Description
object Object

The source object.
predicate function | Object | string <optional>
 _.identity

The function invoked per property.
Returns:

Returns the new object.

Type
Object

(static) property(path) → {function}

Source:

Creates a function that returns the value at path of a given object.

Example
var objects = [
  { 'a': { 'b': { 'c': 2 } } },
  { 'a': { 'b': { 'c': 1 } } }
];

_.map(objects, _.property('a.b.c'));
// => [2, 1]

_.map(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
// => [1, 2]
Parameters:
Name Type Description
path Array | string

The path of the property to get.
Returns:

Returns the new function.

Type
function

(static) propertyOf(object) → {function}

Source:

The opposite of _.property; this method creates a function that returns the value at a given path of object.

Example
var array = [0, 1, 2],
    object = { 'a': array, 'b': array, 'c': array };

_.map(['a[2]', 'c[0]'], _.propertyOf(object));
// => [2, 0]

_.map([['a', '2'], ['c', '0']], _.propertyOf(object));
// => [2, 0]
Parameters:
Name Type Description
object Object

The object to query.
Returns:

Returns the new function.

Type
function

(static) pullAll(array, values) → {Array}

Source:

This method is like _.pull except that it accepts an array of values to remove.

Note: Unlike _.difference, this method mutates array.

Example
var array = [1, 2, 3, 1, 2, 3];

_.pullAll(array, [2, 3]);
console.log(array);
// => [1, 1]
Parameters:
Name Type Description
array Array

The array to modify.
values Array

The values to remove.
Returns:

Returns array.

Type
Array

(static) pullAllBy(array, values, iterateeopt) → {Array}

Source:

This method is like _.pullAll except that it accepts iteratee which is invoked for each element of array and values to generate the criterion by which uniqueness is computed. The iteratee is invoked with one argument: (value).

Note: Unlike _.differenceBy, this method mutates array.

Example
var array = [{ 'x': 1 }, { 'x': 2 }, { 'x': 3 }, { 'x': 1 }];

_.pullAllBy(array, [{ 'x': 1 }, { 'x': 3 }], 'x');
console.log(array);
// => [{ 'x': 2 }]
Parameters:
Name Type Attributes Default Description
array Array

The array to modify.
values Array

The values to remove.
iteratee function | Object | string <optional>
 _.identity

The iteratee invoked per element.
Returns:

Returns array.

Type
Array

(static) random(loweropt, upperopt, floatingopt) → {number}

Source:

Produces a random number between the inclusive lower and upper bounds. If only one argument is provided a number between 0 and the given number is returned. If floating is true, or either lower or upper are floats, a floating-point number is returned instead of an integer.

Note: JavaScript follows the IEEE-754 standard for resolving floating-point values which can produce unexpected results.

Example
_.random(0, 5);
// => an integer between 0 and 5

_.random(5);
// => also an integer between 0 and 5

_.random(5, true);
// => a floating-point number between 0 and 5

_.random(1.2, 5.2);
// => a floating-point number between 1.2 and 5.2
Parameters:
Name Type Attributes Default Description
lower number <optional>
 0

The lower bound.
upper number <optional>
 1

The upper bound.
floating boolean <optional>

Specify returning a floating-point number.
Returns:

Returns the random number.

Type
number

(static) reduce(collection, iterateeopt, accumulatoropt) → {*}

Source:

Reduces collection to a value which is the accumulated result of running each element in collection through iteratee, where each successive invocation is supplied the return value of the previous. If accumulator is not given the first element of collection is used as the initial value. The iteratee is invoked with four arguments: (accumulator, value, index|key, collection).

Many lodash methods are guarded to work as iteratees for methods like _.reduce, _.reduceRight, and _.transform.

The guarded methods are: assign, defaults, defaultsDeep, includes, merge, orderBy, and sortBy

Example
_.reduce([1, 2], function(sum, n) {
  return sum + n;
}, 0);
// => 3

_.reduce({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {
  (result[value] || (result[value] = [])).push(key);
  return result;
}, {});
// => { '1': ['a', 'c'], '2': ['b'] } (iteration order is not guaranteed)
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
accumulator * <optional>

The initial value.
Returns:

Returns the accumulated value.

Type
*

(static) reduceRight(collection, iterateeopt, accumulatoropt) → {*}

Source:

This method is like _.reduce except that it iterates over elements of collection from right to left.

Example
var array = [[0, 1], [2, 3], [4, 5]];

_.reduceRight(array, function(flattened, other) {
  return flattened.concat(other);
}, []);
// => [4, 5, 2, 3, 0, 1]
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
accumulator * <optional>

The initial value.
Returns:

Returns the accumulated value.

Type
*

(static) reject(collection, predicateopt) → {Array}

Source:

The opposite of _.filter; this method returns the elements of collection that predicate does not return truthy for.

Example
var users = [
  { 'user': 'barney', 'age': 36, 'active': false },
  { 'user': 'fred',   'age': 40, 'active': true }
];

_.reject(users, function(o) { return !o.active; });
// => objects for ['fred']

// The `_.matches` iteratee shorthand.
_.reject(users, { 'age': 40, 'active': true });
// => objects for ['barney']

// The `_.matchesProperty` iteratee shorthand.
_.reject(users, ['active', false]);
// => objects for ['fred']

// The `_.property` iteratee shorthand.
_.reject(users, 'active');
// => objects for ['barney']
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the new filtered array.

Type
Array

(static) remove(array, predicateopt) → {Array}

Source:

Removes all elements from array that predicate returns truthy for and returns an array of the removed elements. The predicate is invoked with three arguments: (value, index, array).

Note: Unlike _.filter, this method mutates array. Use _.pull to pull elements from an array by value.

Example
var array = [1, 2, 3, 4];
var evens = _.remove(array, function(n) {
  return n % 2 == 0;
});

console.log(array);
// => [1, 3]

console.log(evens);
// => [2, 4]
Parameters:
Name Type Attributes Default Description
array Array

The array to modify.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the new array of removed elements.

Type
Array

(static) repeat(stringopt, nopt) → {string}

Source:

Repeats the given string n times.

Example
_.repeat('*', 3);
// => '***'

_.repeat('abc', 2);
// => 'abcabc'

_.repeat('abc', 0);
// => ''
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to repeat.
n number <optional>
 0

The number of times to repeat the string.
Returns:

Returns the repeated string.

Type
string

(static) replace(stringopt, pattern, replacement) → {string}

Source:

Replaces matches for pattern in string with replacement.

Note: This method is based on String#replace.

Example
_.replace('Hi Fred', 'Fred', 'Barney');
// => 'Hi Barney'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to modify.
pattern RegExp | string

The pattern to replace.
replacement function | string

The match replacement.
Returns:

Returns the modified string.

Type
string

(static) rest(func, startopt) → {function}

Source:

Creates a function that invokes func with the this binding of the created function and arguments from start and beyond provided as an array.

Note: This method is based on the rest parameter.

Example
var say = _.rest(function(what, names) {
  return what + ' ' + _.initial(names).join(', ') +
    (_.size(names) > 1 ? ', & ' : '') + _.last(names);
});

say('hello', 'fred', 'barney', 'pebbles');
// => 'hello fred, barney, & pebbles'
Parameters:
Name Type Attributes Default Description
func function

The function to apply a rest parameter to.
start number <optional>
 func.length-1

The start position of the rest parameter.
Returns:

Returns the new function.

Type
function

(static) result(object, path, defaultValueopt) → {*}

Source:

This method is like _.get except that if the resolved value is a function it's invoked with the this binding of its parent object and its result is returned.

Example
var object = { 'a': [{ 'b': { 'c1': 3, 'c2': _.constant(4) } }] };

_.result(object, 'a[0].b.c1');
// => 3

_.result(object, 'a[0].b.c2');
// => 4

_.result(object, 'a[0].b.c3', 'default');
// => 'default'

_.result(object, 'a[0].b.c3', _.constant('default'));
// => 'default'
Parameters:
Name Type Attributes Description
object Object

The object to query.
path Array | string

The path of the property to resolve.
defaultValue * <optional>

The value returned if the resolved value is undefined.
Returns:

Returns the resolved value.

Type
*

(static) reverse() → {Array}

Source:

Reverses array so that the first element becomes the last, the second element becomes the second to last, and so on.

Note: This method mutates array and is based on Array#reverse.

Example
var array = [1, 2, 3];

_.reverse(array);
// => [3, 2, 1]

console.log(array);
// => [3, 2, 1]
Returns:

Returns array.

Type
Array

(static) runInContext(contextopt) → {function}

Source:

Create a new pristine lodash function using the context object.

Example
_.mixin({ 'foo': _.constant('foo') });

var lodash = _.runInContext();
lodash.mixin({ 'bar': lodash.constant('bar') });

_.isFunction(_.foo);
// => true
_.isFunction(_.bar);
// => false

lodash.isFunction(lodash.foo);
// => false
lodash.isFunction(lodash.bar);
// => true

// Use `context` to mock `Date#getTime` use in `_.now`.
var mock = _.runInContext({
  'Date': function() {
    return { 'getTime': getTimeMock };
  }
});

// Create a suped-up `defer` in Node.js.
var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;
Parameters:
Name Type Attributes Default Description
context Object <optional>
 root

The context object.
Returns:

Returns a new lodash function.

Type
function

(static) sample(collection) → {*}

Source:

Gets a random element from collection.

Example
_.sample([1, 2, 3, 4]);
// => 2
Parameters:
Name Type Description
collection Array | Object

The collection to sample.
Returns:

Returns the random element.

Type
*

(static) sampleSize(collection, nopt) → {Array}

Source:

Gets n random elements at unique keys from collection up to the size of collection.

Example
_.sampleSize([1, 2, 3], 2);
// => [3, 1]

_.sampleSize([1, 2, 3], 4);
// => [2, 3, 1]
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to sample.
n number <optional>
 0

The number of elements to sample.
Returns:

Returns the random elements.

Type
Array

(static) set(object, path, value) → {Object}

Source:

Sets the value at path of object. If a portion of path doesn't exist it's created. Arrays are created for missing index properties while objects are created for all other missing properties. Use _.setWith to customize path creation.

Note: This method mutates object.

Example
var object = { 'a': [{ 'b': { 'c': 3 } }] };

_.set(object, 'a[0].b.c', 4);
console.log(object.a[0].b.c);
// => 4

_.set(object, 'x[0].y.z', 5);
console.log(object.x[0].y.z);
// => 5
Parameters:
Name Type Description
object Object

The object to modify.
path Array | string

The path of the property to set.
value *

The value to set.
Returns:

Returns object.

Type
Object

(static) setWith(object, path, value, customizeropt) → {Object}

Source:

This method is like _.set except that it accepts customizer which is invoked to produce the objects of path. If customizer returns undefined path creation is handled by the method instead. The customizer is invoked with three arguments: (nsValue, key, nsObject).

Note: This method mutates object.

Example
_.setWith({ '0': { 'length': 2 } }, '[0][1][2]', 3, Object);
// => { '0': { '1': { '2': 3 }, 'length': 2 } }
Parameters:
Name Type Attributes Description
object Object

The object to modify.
path Array | string

The path of the property to set.
value *

The value to set.
customizer function <optional>

The function to customize assigned values.
Returns:

Returns object.

Type
Object

(static) shuffle(collection) → {Array}

Source:

Creates an array of shuffled values, using a version of the Fisher-Yates shuffle.

Example
_.shuffle([1, 2, 3, 4]);
// => [4, 1, 3, 2]
Parameters:
Name Type Description
collection Array | Object

The collection to shuffle.
Returns:

Returns the new shuffled array.

Type
Array

(static) size(collection) → {number}

Source:

Gets the size of collection by returning its length for array-like values or the number of own enumerable properties for objects.

Example
_.size([1, 2, 3]);
// => 3

_.size({ 'a': 1, 'b': 2 });
// => 2

_.size('pebbles');
// => 7
Parameters:
Name Type Description
collection Array | Object

The collection to inspect.
Returns:

Returns the collection size.

Type
number

(static) slice(array, startopt, endopt) → {Array}

Source:

Creates a slice of array from start up to, but not including, end.

Note: This method is used instead of Array#slice to ensure dense arrays are returned.

Parameters:
Name Type Attributes Default Description
array Array

The array to slice.
start number <optional>
 0

The start position.
end number <optional>
 array.length

The end position.
Returns:

Returns the slice of array.

Type
Array

(static) some(collection, predicateopt) → {boolean}

Source:

Checks if predicate returns truthy for any element of collection. Iteration is stopped once predicate returns truthy. The predicate is invoked with three arguments: (value, index|key, collection).

Example
_.some([null, 0, 'yes', false], Boolean);
// => true

var users = [
  { 'user': 'barney', 'active': true },
  { 'user': 'fred',   'active': false }
];

// The `_.matches` iteratee shorthand.
_.some(users, { 'user': 'barney', 'active': false });
// => false

// The `_.matchesProperty` iteratee shorthand.
_.some(users, ['active', false]);
// => true

// The `_.property` iteratee shorthand.
_.some(users, 'active');
// => true
Parameters:
Name Type Attributes Default Description
collection Array | Object

The collection to iterate over.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns true if any element passes the predicate check, else false.

Type
boolean

(static) sortedIndex(array, value) → {number}

Source:

Uses a binary search to determine the lowest index at which value should be inserted into array in order to maintain its sort order.

Example
_.sortedIndex([30, 50], 40);
// => 1

_.sortedIndex([4, 5], 4);
// => 0
Parameters:
Name Type Description
array Array

The sorted array to inspect.
value *

The value to evaluate.
Returns:

Returns the index at which value should be inserted into array.

Type
number

(static) sortedIndexBy(array, value, iterateeopt) → {number}

Source:

This method is like _.sortedIndex except that it accepts iteratee which is invoked for value and each element of array to compute their sort ranking. The iteratee is invoked with one argument: (value).

Example
var dict = { 'thirty': 30, 'forty': 40, 'fifty': 50 };

_.sortedIndexBy(['thirty', 'fifty'], 'forty', _.propertyOf(dict));
// => 1

// The `_.property` iteratee shorthand.
_.sortedIndexBy([{ 'x': 4 }, { 'x': 5 }], { 'x': 4 }, 'x');
// => 0
Parameters:
Name Type Attributes Default Description
array Array

The sorted array to inspect.
value *

The value to evaluate.
iteratee function | Object | string <optional>
 _.identity

The iteratee invoked per element.
Returns:

Returns the index at which value should be inserted into array.

Type
number

(static) sortedIndexOf(array, value) → {number}

Source:

This method is like _.indexOf except that it performs a binary search on a sorted array.

Example
_.sortedIndexOf([1, 1, 2, 2], 2);
// => 2
Parameters:
Name Type Description
array Array

The array to search.
value *

The value to search for.
Returns:

Returns the index of the matched value, else -1.

Type
number

(static) sortedLastIndex(array, value) → {number}

Source:

This method is like _.sortedIndex except that it returns the highest index at which value should be inserted into array in order to maintain its sort order.

Example
_.sortedLastIndex([4, 5], 4);
// => 1
Parameters:
Name Type Description
array Array

The sorted array to inspect.
value *

The value to evaluate.
Returns:

Returns the index at which value should be inserted into array.

Type
number

(static) sortedLastIndexBy(array, value, iterateeopt) → {number}

Source:

This method is like _.sortedLastIndex except that it accepts iteratee which is invoked for value and each element of array to compute their sort ranking. The iteratee is invoked with one argument: (value).

Example
// The `_.property` iteratee shorthand.
_.sortedLastIndexBy([{ 'x': 4 }, { 'x': 5 }], { 'x': 4 }, 'x');
// => 1
Parameters:
Name Type Attributes Default Description
array Array

The sorted array to inspect.
value *

The value to evaluate.
iteratee function | Object | string <optional>
 _.identity

The iteratee invoked per element.
Returns:

Returns the index at which value should be inserted into array.

Type
number

(static) sortedLastIndexOf(array, value) → {number}

Source:

This method is like _.lastIndexOf except that it performs a binary search on a sorted array.

Example
_.sortedLastIndexOf([1, 1, 2, 2], 2);
// => 3
Parameters:
Name Type Description
array Array

The array to search.
value *

The value to search for.
Returns:

Returns the index of the matched value, else -1.

Type
number

(static) sortedUniq(array) → {Array}

Source:

This method is like _.uniq except that it's designed and optimized for sorted arrays.

Example
_.sortedUniq([1, 1, 2]);
// => [1, 2]
Parameters:
Name Type Description
array Array

The array to inspect.
Returns:

Returns the new duplicate free array.

Type
Array

(static) sortedUniqBy(array, iterateeopt) → {Array}

Source:

This method is like _.uniqBy except that it's designed and optimized for sorted arrays.

Example
_.sortedUniqBy([1.1, 1.2, 2.3, 2.4], Math.floor);
// => [1.1, 2.3]
Parameters:
Name Type Attributes Description
array Array

The array to inspect.
iteratee function <optional>

The iteratee invoked per element.
Returns:

Returns the new duplicate free array.

Type
Array

(static) split(stringopt, separator, limitopt) → {Array}

Source:

Splits string by separator.

Note: This method is based on String#split.

Example
_.split('a-b-c', '-', 2);
// => ['a', 'b']
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to split.
separator RegExp | string

The separator pattern to split by.
limit number <optional>

The length to truncate results to.
Returns:

Returns the new array of string segments.

Type
Array

(static) spread(func, startopt) → {function}

Source:

Creates a function that invokes func with the this binding of the created function and an array of arguments much like Function#apply.

Note: This method is based on the spread operator.

Example
var say = _.spread(function(who, what) {
  return who + ' says ' + what;
});

say(['fred', 'hello']);
// => 'fred says hello'

var numbers = Promise.all([
  Promise.resolve(40),
  Promise.resolve(36)
]);

numbers.then(_.spread(function(x, y) {
  return x + y;
}));
// => a Promise of 76
Parameters:
Name Type Attributes Default Description
func function

The function to spread arguments over.
start number <optional>
 0

The start position of the spread.
Returns:

Returns the new function.

Type
function

(static) startsWith(stringopt, targetopt, positionopt) → {boolean}

Source:

Checks if string starts with the given target string.

Example
_.startsWith('abc', 'a');
// => true

_.startsWith('abc', 'b');
// => false

_.startsWith('abc', 'b', 1);
// => true
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to search.
target string <optional>

The string to search for.
position number <optional>
 0

The position to search from.
Returns:

Returns true if string starts with target, else false.

Type
boolean

(static) subtract(minuend, subtrahend) → {number}

Source:

Subtract two numbers.

Example
_.subtract(6, 4);
// => 2
Parameters:
Name Type Description
minuend number

The first number in a subtraction.
subtrahend number

The second number in a subtraction.
Returns:

Returns the difference.

Type
number

(static) sum(array) → {number}

Source:

Computes the sum of the values in array.

Example
_.sum([4, 2, 8, 6]);
// => 20
Parameters:
Name Type Description
array Array

The array to iterate over.
Returns:

Returns the sum.

Type
number

(static) sumBy(array, iterateeopt) → {number}

Source:

This method is like _.sum except that it accepts iteratee which is invoked for each element in array to generate the value to be summed. The iteratee is invoked with one argument: (value).

Example
var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];

_.sumBy(objects, function(o) { return o.n; });
// => 20

// The `_.property` iteratee shorthand.
_.sumBy(objects, 'n');
// => 20
Parameters:
Name Type Attributes Default Description
array Array

The array to iterate over.
iteratee function | Object | string <optional>
 _.identity

The iteratee invoked per element.
Returns:

Returns the sum.

Type
number

(static) tail(array) → {Array}

Source:

Gets all but the first element of array.

Example
_.tail([1, 2, 3]);
// => [2, 3]
Parameters:
Name Type Description
array Array

The array to query.
Returns:

Returns the slice of array.

Type
Array

(static) take(array, nopt) → {Array}

Source:

Creates a slice of array with n elements taken from the beginning.

Example
_.take([1, 2, 3]);
// => [1]

_.take([1, 2, 3], 2);
// => [1, 2]

_.take([1, 2, 3], 5);
// => [1, 2, 3]

_.take([1, 2, 3], 0);
// => []
Parameters:
Name Type Attributes Default Description
array Array

The array to query.
n number <optional>
 1

The number of elements to take.
Returns:

Returns the slice of array.

Type
Array

(static) takeRight(array, nopt) → {Array}

Source:

Creates a slice of array with n elements taken from the end.

Example
_.takeRight([1, 2, 3]);
// => [3]

_.takeRight([1, 2, 3], 2);
// => [2, 3]

_.takeRight([1, 2, 3], 5);
// => [1, 2, 3]

_.takeRight([1, 2, 3], 0);
// => []
Parameters:
Name Type Attributes Default Description
array Array

The array to query.
n number <optional>
 1

The number of elements to take.
Returns:

Returns the slice of array.

Type
Array

(static) takeRightWhile(array, predicateopt) → {Array}

Source:

Creates a slice of array with elements taken from the end. Elements are taken until predicate returns falsey. The predicate is invoked with three arguments: (value, index, array).

Example
var users = [
  { 'user': 'barney',  'active': true },
  { 'user': 'fred',    'active': false },
  { 'user': 'pebbles', 'active': false }
];

_.takeRightWhile(users, function(o) { return !o.active; });
// => objects for ['fred', 'pebbles']

// The `_.matches` iteratee shorthand.
_.takeRightWhile(users, { 'user': 'pebbles', 'active': false });
// => objects for ['pebbles']

// The `_.matchesProperty` iteratee shorthand.
_.takeRightWhile(users, ['active', false]);
// => objects for ['fred', 'pebbles']

// The `_.property` iteratee shorthand.
_.takeRightWhile(users, 'active');
// => []
Parameters:
Name Type Attributes Default Description
array Array

The array to query.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the slice of array.

Type
Array

(static) takeWhile(array, predicateopt) → {Array}

Source:

Creates a slice of array with elements taken from the beginning. Elements are taken until predicate returns falsey. The predicate is invoked with three arguments: (value, index, array).

Example
var users = [
  { 'user': 'barney',  'active': false },
  { 'user': 'fred',    'active': false},
  { 'user': 'pebbles', 'active': true }
];

_.takeWhile(users, function(o) { return !o.active; });
// => objects for ['barney', 'fred']

// The `_.matches` iteratee shorthand.
_.takeWhile(users, { 'user': 'barney', 'active': false });
// => objects for ['barney']

// The `_.matchesProperty` iteratee shorthand.
_.takeWhile(users, ['active', false]);
// => objects for ['barney', 'fred']

// The `_.property` iteratee shorthand.
_.takeWhile(users, 'active');
// => []
Parameters:
Name Type Attributes Default Description
array Array

The array to query.
predicate function | Object | string <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the slice of array.

Type
Array

(static) tap(value, interceptor) → {*}

Source:

This method invokes interceptor and returns value. The interceptor is invoked with one argument; (value). The purpose of this method is to "tap into" a method chain in order to modify intermediate results.

Example
_([1, 2, 3])
 .tap(function(array) {
   // Mutate input array.
   array.pop();
 })
 .reverse()
 .value();
// => [2, 1]
Parameters:
Name Type Description
value *

The value to provide to interceptor.
interceptor function

The function to invoke.
Returns:

Returns value.

Type
*

(static) template(stringopt, optionsopt) → {function}

Source:

Creates a compiled template function that can interpolate data properties in "interpolate" delimiters, HTML-escape interpolated data properties in "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data properties may be accessed as free variables in the template. If a setting object is given it takes precedence over _.templateSettings values.

Note: In the development build _.template utilizes sourceURLs for easier debugging.

For more information on precompiling templates see lodash's custom builds documentation.

For more information on Chrome extension sandboxes see Chrome's extensions documentation.

Example
// Use the "interpolate" delimiter to create a compiled template.
var compiled = _.template('hello <%= user %>!');
compiled({ 'user': 'fred' });
// => 'hello fred!'

// Use the HTML "escape" delimiter to escape data property values.
var compiled = _.template('<b><%- value %></b>');
compiled({ 'value': '<script>' });
// => '<b>&lt;script&gt;</b>'

// Use the "evaluate" delimiter to execute JavaScript and generate HTML.
var compiled = _.template('<% _.forEach(users, function(user) { %><li><%- user %></li><% }); %>');
compiled({ 'users': ['fred', 'barney'] });
// => '<li>fred</li><li>barney</li>'

// Use the internal `print` function in "evaluate" delimiters.
var compiled = _.template('<% print("hello " + user); %>!');
compiled({ 'user': 'barney' });
// => 'hello barney!'

// Use the ES delimiter as an alternative to the default "interpolate" delimiter.
var compiled = _.template('hello ${ user }!');
compiled({ 'user': 'pebbles' });
// => 'hello pebbles!'

// Use custom template delimiters.
_.templateSettings.interpolate = /{{([\s\S]+?)}}/g;
var compiled = _.template('hello {{ user }}!');
compiled({ 'user': 'mustache' });
// => 'hello mustache!'

// Use backslashes to treat delimiters as plain text.
var compiled = _.template('<%= "\\<%- value %\\>" %>');
compiled({ 'value': 'ignored' });
// => '<%- value %>'

// Use the `imports` option to import `jQuery` as `jq`.
var text = '<% jq.each(users, function(user) { %><li><%- user %></li><% }); %>';
var compiled = _.template(text, { 'imports': { 'jq': jQuery } });
compiled({ 'users': ['fred', 'barney'] });
// => '<li>fred</li><li>barney</li>'

// Use the `sourceURL` option to specify a custom sourceURL for the template.
var compiled = _.template('hello <%= user %>!', { 'sourceURL': '/basic/greeting.jst' });
compiled(data);
// => find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector

// Use the `variable` option to ensure a with-statement isn't used in the compiled template.
var compiled = _.template('hi <%= data.user %>!', { 'variable': 'data' });
compiled.source;
// => function(data) {
//   var __t, __p = '';
//   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';
//   return __p;
// }

// Use the `source` property to inline compiled templates for meaningful
// line numbers in error messages and stack traces.
fs.writeFileSync(path.join(cwd, 'jst.js'), '\
  var JST = {\
    "main": ' + _.template(mainText).source + '\
  };\
');
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The template string.
options Object <optional>

The options object.

Properties
Name Type Attributes Description
escape RegExp <optional>

The HTML "escape" delimiter.
evaluate RegExp <optional>

The "evaluate" delimiter.
imports Object <optional>

An object to import into the template as free variables.
interpolate RegExp <optional>

The "interpolate" delimiter.
sourceURL string <optional>

The sourceURL of the template's compiled source.
variable string <optional>

The data object variable name.
Returns:

Returns the compiled template function.

Type
function

(static) throttle(func, waitopt, optionsopt) → {function}

Source:

Creates a throttled function that only invokes func at most once per every wait milliseconds. The throttled function comes with a cancel method to cancel delayed func invocations and a flush method to immediately invoke them. Provide an options object to indicate whether func should be invoked on the leading and/or trailing edge of the wait timeout. The func is invoked with the last arguments provided to the throttled function. Subsequent calls to the throttled function return the result of the last func invocation.

Note: If leading and trailing options are true, func is invoked on the trailing edge of the timeout only if the throttled function is invoked more than once during the wait timeout.

See David Corbacho's article for details over the differences between _.throttle and _.debounce.

Example
// Avoid excessively updating the position while scrolling.
jQuery(window).on('scroll', _.throttle(updatePosition, 100));

// Invoke `renewToken` when the click event is fired, but not more than once every 5 minutes.
var throttled = _.throttle(renewToken, 300000, { 'trailing': false });
jQuery(element).on('click', throttled);

// Cancel the trailing throttled invocation.
jQuery(window).on('popstate', throttled.cancel);
Parameters:
Name Type Attributes Default Description
func function

The function to throttle.
wait number <optional>
 0

The number of milliseconds to throttle invocations to.
options Object <optional>

The options object.

Properties
Name Type Attributes Default Description
leading boolean <optional>
 true

Specify invoking on the leading edge of the timeout.
trailing boolean <optional>
 true

Specify invoking on the trailing edge of the timeout.
Returns:

Returns the new throttled function.

Type
function

(static) thru(value, interceptor) → {*}

Source:

This method is like _.tap except that it returns the result of interceptor. The purpose of this method is to "pass thru" values replacing intermediate results in a method chain.

Example
_('  abc  ')
 .chain()
 .trim()
 .thru(function(value) {
   return [value];
 })
 .value();
// => ['abc']
Parameters:
Name Type Description
value *

The value to provide to interceptor.
interceptor function

The function to invoke.
Returns:

Returns the result of interceptor.

Type
*

(static) times(n, iterateeopt) → {Array}

Source:

Invokes the iteratee n times, returning an array of the results of each invocation. The iteratee is invoked with one argument; (index).

Example
_.times(3, String);
// => ['0', '1', '2']

 _.times(4, _.constant(true));
// => [true, true, true, true]
Parameters:
Name Type Attributes Default Description
n number

The number of times to invoke iteratee.
iteratee function <optional>
 _.identity

The function invoked per iteration.
Returns:

Returns the array of results.

Type
Array

(static) toArray(value) → {Array}

Source:

Converts value to an array.

Example
_.toArray({ 'a': 1, 'b': 2 });
// => [1, 2]

_.toArray('abc');
// => ['a', 'b', 'c']

_.toArray(1);
// => []

_.toArray(null);
// => []
Parameters:
Name Type Description
value *

The value to convert.
Returns:

Returns the converted array.

Type
Array

(static) toInteger(value) → {number}

Source:

Converts value to an integer.

Note: This function is loosely based on ToInteger.

Example
_.toInteger(3);
// => 3

_.toInteger(Number.MIN_VALUE);
// => 0

_.toInteger(Infinity);
// => 1.7976931348623157e+308

_.toInteger('3');
// => 3
Parameters:
Name Type Description
value *

The value to convert.
Returns:

Returns the converted integer.

Type
number

(static) toLength(value) → {number}

Source:

Converts value to an integer suitable for use as the length of an array-like object.

Note: This method is based on ToLength.

Example
_.toLength(3);
// => 3

_.toLength(Number.MIN_VALUE);
// => 0

_.toLength(Infinity);
// => 4294967295

_.toLength('3');
// => 3
Parameters:
Name Type Description
value *

The value to convert.
Returns:

Returns the converted integer.

Type
number

(static) toLower(stringopt) → {string}

Source:

Converts string, as a whole, to lower case.

Example
_.toLower('--Foo-Bar');
// => '--foo-bar'

_.toLower('fooBar');
// => 'foobar'

_.toLower('__FOO_BAR__');
// => '__foo_bar__'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to convert.
Returns:

Returns the lower cased string.

Type
string

(static) toNumber(value) → {number}

Source:

Converts value to a number.

Example
_.toNumber(3);
// => 3

_.toNumber(Number.MIN_VALUE);
// => 5e-324

_.toNumber(Infinity);
// => Infinity

_.toNumber('3');
// => 3
Parameters:
Name Type Description
value *

The value to process.
Returns:

Returns the number.

Type
number

(static) toPairs(object) → {Array}

Source:

Creates an array of own enumerable key-value pairs for object which can be consumed by _.fromPairs.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.toPairs(new Foo);
// => [['a', 1], ['b', 2]] (iteration order is not guaranteed)
Parameters:
Name Type Description
object Object

The object to query.
Returns:

Returns the new array of key-value pairs.

Type
Array

(static) toPairsIn(object) → {Array}

Source:

Creates an array of own and inherited enumerable key-value pairs for object which can be consumed by _.fromPairs.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.toPairsIn(new Foo);
// => [['a', 1], ['b', 2], ['c', 1]] (iteration order is not guaranteed)
Parameters:
Name Type Description
object Object

The object to query.
Returns:

Returns the new array of key-value pairs.

Type
Array

(static) toPath(value) → {Array}

Source:

Converts value to a property path array.

Example
_.toPath('a.b.c');
// => ['a', 'b', 'c']

_.toPath('a[0].b.c');
// => ['a', '0', 'b', 'c']

var path = ['a', 'b', 'c'],
    newPath = _.toPath(path);

console.log(newPath);
// => ['a', 'b', 'c']

console.log(path === newPath);
// => false
Parameters:
Name Type Description
value *

The value to convert.
Returns:

Returns the new property path array.

Type
Array

(static) toPlainObject(value) → {Object}

Source:

Converts value to a plain object flattening inherited enumerable properties of value to own properties of the plain object.

Example
function Foo() {
  this.b = 2;
}

Foo.prototype.c = 3;

_.assign({ 'a': 1 }, new Foo);
// => { 'a': 1, 'b': 2 }

_.assign({ 'a': 1 }, _.toPlainObject(new Foo));
// => { 'a': 1, 'b': 2, 'c': 3 }
Parameters:
Name Type Description
value *

The value to convert.
Returns:

Returns the converted plain object.

Type
Object

(static) toSafeInteger(value) → {number}

Source:

Converts value to a safe integer. A safe integer can be compared and represented correctly.

Example
_.toSafeInteger(3);
// => 3

_.toSafeInteger(Number.MIN_VALUE);
// => 0

_.toSafeInteger(Infinity);
// => 9007199254740991

_.toSafeInteger('3');
// => 3
Parameters:
Name Type Description
value *

The value to convert.
Returns:

Returns the converted integer.

Type
number

(static) toString(value) → {string}

Source:

Converts value to a string if it's not one. An empty string is returned for null and undefined values. The sign of -0 is preserved.

Example
_.toString(null);
// => ''

_.toString(-0);
// => '-0'

_.toString([1, 2, 3]);
// => '1,2,3'
Parameters:
Name Type Description
value *

The value to process.
Returns:

Returns the string.

Type
string

(static) toUpper(stringopt) → {string}

Source:

Converts string, as a whole, to upper case.

Example
_.toUpper('--foo-bar');
// => '--FOO-BAR'

_.toUpper('fooBar');
// => 'FOOBAR'

_.toUpper('__foo_bar__');
// => '__FOO_BAR__'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to convert.
Returns:

Returns the upper cased string.

Type
string

(static) transform(object, iterateeopt, accumulatoropt) → {*}

Source:

An alternative to _.reduce; this method transforms object to a new accumulator object which is the result of running each of its own enumerable properties through iteratee, with each invocation potentially mutating the accumulator object. The iteratee is invoked with four arguments: (accumulator, value, key, object). Iteratee functions may exit iteration early by explicitly returning false.

Example
_.transform([2, 3, 4], function(result, n) {
  result.push(n *= n);
  return n % 2 == 0;
}, []);
// => [4, 9]

_.transform({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {
  (result[value] || (result[value] = [])).push(key);
}, {});
// => { '1': ['a', 'c'], '2': ['b'] }
Parameters:
Name Type Attributes Default Description
object Array | Object

The object to iterate over.
iteratee function <optional>
 _.identity

The function invoked per iteration.
accumulator * <optional>

The custom accumulator value.
Returns:

Returns the accumulated value.

Type
*

(static) trim(stringopt, charsopt) → {string}

Source:

Removes leading and trailing whitespace or specified characters from string.

Example
_.trim('  abc  ');
// => 'abc'

_.trim('-_-abc-_-', '_-');
// => 'abc'

_.map(['  foo  ', '  bar  '], _.trim);
// => ['foo', 'bar']
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to trim.
chars string <optional>
 whitespace

The characters to trim.
Returns:

Returns the trimmed string.

Type
string

(static) trimEnd(stringopt, charsopt) → {string}

Source:

Removes trailing whitespace or specified characters from string.

Example
_.trimEnd('  abc  ');
// => '  abc'

_.trimEnd('-_-abc-_-', '_-');
// => '-_-abc'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to trim.
chars string <optional>
 whitespace

The characters to trim.
Returns:

Returns the trimmed string.

Type
string

(static) trimStart(stringopt, charsopt) → {string}

Source:

Removes leading whitespace or specified characters from string.

Example
_.trimStart('  abc  ');
// => 'abc  '

_.trimStart('-_-abc-_-', '_-');
// => 'abc-_-'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to trim.
chars string <optional>
 whitespace

The characters to trim.
Returns:

Returns the trimmed string.

Type
string

(static) truncate(stringopt, optionsopt) → {string}

Source:

Truncates string if it's longer than the given maximum string length. The last characters of the truncated string are replaced with the omission string which defaults to "...".

Example
_.truncate('hi-diddly-ho there, neighborino');
// => 'hi-diddly-ho there, neighbo...'

_.truncate('hi-diddly-ho there, neighborino', {
  'length': 24,
  'separator': ' '
});
// => 'hi-diddly-ho there,...'

_.truncate('hi-diddly-ho there, neighborino', {
  'length': 24,
  'separator': /,? +/
});
// => 'hi-diddly-ho there...'

_.truncate('hi-diddly-ho there, neighborino', {
  'omission': ' [...]'
});
// => 'hi-diddly-ho there, neig [...]'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to truncate.
options Object <optional>
 ({})

The options object.

Properties
Name Type Attributes Default Description
length number <optional>
 30

The maximum string length.
omission string <optional>
 '...'

The string to indicate text is omitted.
separator RegExp | string <optional>

The separator pattern to truncate to.
Returns:

Returns the truncated string.

Type
string

(static) unary(func) → {function}

Source:

Creates a function that accepts up to one argument, ignoring any additional arguments.

Example
_.map(['6', '8', '10'], _.unary(parseInt));
// => [6, 8, 10]
Parameters:
Name Type Description
func function

The function to cap arguments for.
Returns:

Returns the new function.

Type
function

(static) unescape(stringopt) → {string}

Source:

The inverse of _.escape; this method converts the HTML entities &amp;, &lt;, &gt;, &quot;, &#39;, and &#96; in string to their corresponding characters.

Note: No other HTML entities are unescaped. To unescape additional HTML entities use a third-party library like he.

Example
_.unescape('fred, barney, &amp; pebbles');
// => 'fred, barney, & pebbles'
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to unescape.
Returns:

Returns the unescaped string.

Type
string

(static) uniq(array) → {Array}

Source:

Creates a duplicate-free version of an array, using SameValueZero for equality comparisons, in which only the first occurrence of each element is kept.

Example
_.uniq([2, 1, 2]);
// => [2, 1]
Parameters:
Name Type Description
array Array

The array to inspect.
Returns:

Returns the new duplicate free array.

Type
Array

(static) uniqBy(array, iterateeopt) → {Array}

Source:

This method is like _.uniq except that it accepts iteratee which is invoked for each element in array to generate the criterion by which uniqueness is computed. The iteratee is invoked with one argument: (value).

Example
_.uniqBy([2.1, 1.2, 2.3], Math.floor);
// => [2.1, 1.2]

// The `_.property` iteratee shorthand.
_.uniqBy([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 1 }, { 'x': 2 }]
Parameters:
Name Type Attributes Default Description
array Array

The array to inspect.
iteratee function | Object | string <optional>
 _.identity

The iteratee invoked per element.
Returns:

Returns the new duplicate free array.

Type
Array

(static) uniqueId(prefixopt) → {string}

Source:

Generates a unique ID. If prefix is given the ID is appended to it.

Example
_.uniqueId('contact_');
// => 'contact_104'

_.uniqueId();
// => '105'
Parameters:
Name Type Attributes Default Description
prefix string <optional>
 ''

The value to prefix the ID with.
Returns:

Returns the unique ID.

Type
string

(static) uniqWith(array, comparatoropt) → {Array}

Source:

This method is like _.uniq except that it accepts comparator which is invoked to compare elements of array. The comparator is invoked with two arguments: (arrVal, othVal).

Example
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 },  { 'x': 1, 'y': 2 }];

_.uniqWith(objects, _.isEqual);
// => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }]
Parameters:
Name Type Attributes Description
array Array

The array to inspect.
comparator function <optional>

The comparator invoked per element.
Returns:

Returns the new duplicate free array.

Type
Array

(static) unset(object, path) → {boolean}

Source:

Removes the property at path of object.

Note: This method mutates object.

Example
var object = { 'a': [{ 'b': { 'c': 7 } }] };
_.unset(object, 'a[0].b.c');
// => true

console.log(object);
// => { 'a': [{ 'b': {} }] };

_.unset(object, 'a[0].b.c');
// => true

console.log(object);
// => { 'a': [{ 'b': {} }] };
Parameters:
Name Type Description
object Object

The object to modify.
path Array | string

The path of the property to unset.
Returns:

Returns true if the property is deleted, else false.

Type
boolean

(static) unzip(array) → {Array}

Source:

This method is like _.zip except that it accepts an array of grouped elements and creates an array regrouping the elements to their pre-zip configuration.

Example
var zipped = _.zip(['fred', 'barney'], [30, 40], [true, false]);
// => [['fred', 30, true], ['barney', 40, false]]

_.unzip(zipped);
// => [['fred', 'barney'], [30, 40], [true, false]]
Parameters:
Name Type Description
array Array

The array of grouped elements to process.
Returns:

Returns the new array of regrouped elements.

Type
Array

(static) unzipWith(array, iterateeopt) → {Array}

Source:

This method is like _.unzip except that it accepts iteratee to specify how regrouped values should be combined. The iteratee is invoked with the elements of each group: (...group).

Example
var zipped = _.zip([1, 2], [10, 20], [100, 200]);
// => [[1, 10, 100], [2, 20, 200]]

_.unzipWith(zipped, _.add);
// => [3, 30, 300]
Parameters:
Name Type Attributes Default Description
array Array

The array of grouped elements to process.
iteratee function <optional>
 _.identity

The function to combine regrouped values.
Returns:

Returns the new array of regrouped elements.

Type
Array

(static) values(object) → {Array}

Source:

Creates an array of the own enumerable property values of object.

Note: Non-object values are coerced to objects.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.values(new Foo);
// => [1, 2] (iteration order is not guaranteed)

_.values('hi');
// => ['h', 'i']
Parameters:
Name Type Description
object Object

The object to query.
Returns:

Returns the array of property values.

Type
Array

(static) valuesIn(object) → {Array}

Source:

Creates an array of the own and inherited enumerable property values of object.

Note: Non-object values are coerced to objects.

Example
function Foo() {
  this.a = 1;
  this.b = 2;
}

Foo.prototype.c = 3;

_.valuesIn(new Foo);
// => [1, 2, 3] (iteration order is not guaranteed)
Parameters:
Name Type Description
object Object

The object to query.
Returns:

Returns the array of property values.

Type
Array

(static) words(stringopt, patternopt) → {Array}

Source:

Splits string into an array of its words.

Example
_.words('fred, barney, & pebbles');
// => ['fred', 'barney', 'pebbles']

_.words('fred, barney, & pebbles', /[^, ]+/g);
// => ['fred', 'barney', '&', 'pebbles']
Parameters:
Name Type Attributes Default Description
string string <optional>
 ''

The string to inspect.
pattern RegExp | string <optional>

The pattern to match words.
Returns:

Returns the words of string.

Type
Array

(static) wrap(value, wrapperopt) → {function}

Source:

Creates a function that provides value to the wrapper function as its first argument. Any additional arguments provided to the function are appended to those provided to the wrapper function. The wrapper is invoked with the this binding of the created function.

Example
var p = _.wrap(_.escape, function(func, text) {
  return '<p>' + func(text) + '</p>';
});

p('fred, barney, & pebbles');
// => '<p>fred, barney, &amp; pebbles</p>'
Parameters:
Name Type Attributes Default Description
value *

The value to wrap.
wrapper function <optional>
 identity

The wrapper function.
Returns:

Returns the new function.

Type
function

(static) zipObject(propsopt, valuesopt) → {Object}

Source:

This method is like _.fromPairs except that it accepts two arrays, one of property names and one of corresponding values.

Example
_.zipObject(['a', 'b'], [1, 2]);
// => { 'a': 1, 'b': 2 }
Parameters:
Name Type Attributes Default Description
props Array <optional>
 []

The property names.
values Array <optional>
 []

The property values.
Returns:

Returns the new object.

Type
Object

(static) zipObjectDeep(propsopt, valuesopt) → {Object}

Source:

This method is like _.zipObject except that it supports property paths.

Example
_.zipObjectDeep(['a.b[0].c', 'a.b[1].d'], [1, 2]);
// => { 'a': { 'b': [{ 'c': 1 }, { 'd': 2 }] } }
Parameters:
Name Type Attributes Default Description
props Array <optional>
 []

The property names.
values Array <optional>
 []

The property values.
Returns:

Returns the new object.

Type
Object