_.compact_.difference_.drop_.findIndex_.first_.flatten_.head_.indexOf_.initial_.intersection_.last_.lastIndexOf_.object_.range_.rest_.sortedIndex_.tail_.take_.union_.uniq_.unique_.unzip_.without_.zip_.zipObject
_.all_.any_.at_.collect_.contains_.countBy_.detect_.each_.every_.filter_.find_.findWhere_.foldl_.foldr_.forEach_.groupBy_.include_.inject_.invoke_.map_.max_.min_.pluck_.reduce_.reduceRight_.reject_.select_.shuffle_.size_.some_.sortBy_.toArray_.where
_.after_.bind_.bindAll_.bindKey_.compose_.createCallback_.debounce_.defer_.delay_.memoize_.once_.partial_.partialRight_.throttle_.wrap
_.assign_.clone_.cloneDeep_.defaults_.extend_.findKey_.forIn_.forOwn_.functions_.has_.invert_.isArguments_.isArray_.isBoolean_.isDate_.isElement_.isEmpty_.isEqual_.isFinite_.isFunction_.isNaN_.isNull_.isNumber_.isObject_.isPlainObject_.isRegExp_.isString_.isUndefined_.keys_.merge_.methods_.omit_.pairs_.pick_.transform_.values
_.escape_.identity_.mixin_.noConflict_.parseInt_.random_.result_.runInContext_.template_.times_.unescape_.uniqueId
_.VERSION_.support_.support.argsClass_.support.argsObject_.support.enumErrorProps_.support.enumPrototypes_.support.fastBind_.support.nonEnumArgs_.support.nonEnumShadows_.support.ownLast_.support.spliceObjects_.support.unindexedChars_.templateSettings_.templateSettings.escape_.templateSettings.evaluate_.templateSettings.interpolate_.templateSettings.variable_.templateSettings.imports
Creates an array with all falsey values of array removed. The values false, null, 0, "", undefined and NaN are all falsey.
array(Array): The array to compact.
(Array): Returns a new filtered array.
_.compact([0, 1, false, 2, '', 3]);
// => [1, 2, 3]Creates an array of array elements not present in the other arrays using strict equality for comparisons, i.e. ===.
array(Array): The array to process.[array1, array2, ...](Array): Arrays to check.
(Array): Returns a new array of array elements not present in the other arrays.
_.difference([1, 2, 3, 4, 5], [5, 2, 10]);
// => [1, 3, 4]This method is similar to _.find, except that it returns the index of the element that passes the callback check, instead of the element itself.
array(Array): The array to search.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the index of the found element, else -1.
_.findIndex(['apple', 'banana', 'beet'], function(food) {
return /^b/.test(food);
});
// => 1Gets the first element of the array. If a number n is passed, the first n elements of the array are returned. If a callback function is passed, elements at the beginning of the array are returned as long as the callback returns truthy. The callback is bound to thisArg and invoked with three arguments; (value, index, array).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
head, take
array(Array): The array to query.[callback|n](Function|Object|Number|String): The function called per element or the number of elements to return. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the first element(s) of array.
_.first([1, 2, 3]);
// => 1
_.first([1, 2, 3], 2);
// => [1, 2]
_.first([1, 2, 3], function(num) {
return num < 3;
});
// => [1, 2]
var food = [
{ 'name': 'banana', 'organic': true },
{ 'name': 'beet', 'organic': false },
];
// using "_.pluck" callback shorthand
_.first(food, 'organic');
// => [{ 'name': 'banana', 'organic': true }]
var food = [
{ 'name': 'apple', 'type': 'fruit' },
{ 'name': 'banana', 'type': 'fruit' },
{ 'name': 'beet', 'type': 'vegetable' }
];
// using "_.where" callback shorthand
_.first(food, { 'type': 'fruit' });
// => [{ 'name': 'apple', 'type': 'fruit' }, { 'name': 'banana', 'type': 'fruit' }]Flattens a nested array (the nesting can be to any depth). If isShallow is truthy, array will only be flattened a single level. If callback is passed, each element of array is passed through a callback before flattening. The callback is bound to thisArg and invoked with three arguments; (value, index, array).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
array(Array): The array to flatten.[isShallow=false](Boolean): A flag to indicate only flattening a single level.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a new flattened array.
_.flatten([1, [2], [3, [[4]]]]);
// => [1, 2, 3, 4];
_.flatten([1, [2], [3, [[4]]]], true);
// => [1, 2, 3, [[4]]];
var stooges = [
{ 'name': 'curly', 'quotes': ['Oh, a wise guy, eh?', 'Poifect!'] },
{ 'name': 'moe', 'quotes': ['Spread out!', 'You knucklehead!'] }
];
// using "_.pluck" callback shorthand
_.flatten(stooges, 'quotes');
// => ['Oh, a wise guy, eh?', 'Poifect!', 'Spread out!', 'You knucklehead!']Gets the index at which the first occurrence of value is found using strict equality for comparisons, i.e. ===. If the array is already sorted, passing true for fromIndex will run a faster binary search.
array(Array): The array to search.value(Mixed): The value to search for.[fromIndex=0](Boolean|Number): The index to search from ortrueto perform a binary search on a sortedarray.
(Number): Returns the index of the matched value or -1.
_.indexOf([1, 2, 3, 1, 2, 3], 2);
// => 1
_.indexOf([1, 2, 3, 1, 2, 3], 2, 3);
// => 4
_.indexOf([1, 1, 2, 2, 3, 3], 2, true);
// => 2Gets all but the last element of array. If a number n is passed, the last n elements are excluded from the result. If a callback function is passed, elements at the end of the array are excluded from the result as long as the callback returns truthy. The callback is bound to thisArg and invoked with three arguments; (value, index, array).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
array(Array): The array to query.[callback|n=1](Function|Object|Number|String): The function called per element or the number of elements to exclude. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a slice of array.
_.initial([1, 2, 3]);
// => [1, 2]
_.initial([1, 2, 3], 2);
// => [1]
_.initial([1, 2, 3], function(num) {
return num > 1;
});
// => [1]
var food = [
{ 'name': 'beet', 'organic': false },
{ 'name': 'carrot', 'organic': true }
];
// using "_.pluck" callback shorthand
_.initial(food, 'organic');
// => [{ 'name': 'beet', 'organic': false }]
var food = [
{ 'name': 'banana', 'type': 'fruit' },
{ 'name': 'beet', 'type': 'vegetable' },
{ 'name': 'carrot', 'type': 'vegetable' }
];
// using "_.where" callback shorthand
_.initial(food, { 'type': 'vegetable' });
// => [{ 'name': 'banana', 'type': 'fruit' }]Computes the intersection of all the passed-in arrays using strict equality for comparisons, i.e. ===.
[array1, array2, ...](Array): Arrays to process.
(Array): Returns a new array of unique elements that are present in all of the arrays.
_.intersection([1, 2, 3], [101, 2, 1, 10], [2, 1]);
// => [1, 2]Gets the last element of the array. If a number n is passed, the last n elements of the array are returned. If a callback function is passed, elements at the end of the array are returned as long as the callback returns truthy. The callback is bound to thisArg and invoked with three arguments;(value, index, array).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
array(Array): The array to query.[callback|n](Function|Object|Number|String): The function called per element or the number of elements to return. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the last element(s) of array.
_.last([1, 2, 3]);
// => 3
_.last([1, 2, 3], 2);
// => [2, 3]
_.last([1, 2, 3], function(num) {
return num > 1;
});
// => [2, 3]
var food = [
{ 'name': 'beet', 'organic': false },
{ 'name': 'carrot', 'organic': true }
];
// using "_.pluck" callback shorthand
_.last(food, 'organic');
// => [{ 'name': 'carrot', 'organic': true }]
var food = [
{ 'name': 'banana', 'type': 'fruit' },
{ 'name': 'beet', 'type': 'vegetable' },
{ 'name': 'carrot', 'type': 'vegetable' }
];
// using "_.where" callback shorthand
_.last(food, { 'type': 'vegetable' });
// => [{ 'name': 'beet', 'type': 'vegetable' }, { 'name': 'carrot', 'type': 'vegetable' }]Gets the index at which the last occurrence of value is found using strict equality for comparisons, i.e. ===. If fromIndex is negative, it is used as the offset from the end of the collection.
array(Array): The array to search.value(Mixed): The value to search for.[fromIndex=array.length-1](Number): The index to search from.
(Number): Returns the index of the matched value or -1.
_.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
// => 4
_.lastIndexOf([1, 2, 3, 1, 2, 3], 2, 3);
// => 1Creates an array of numbers (positive and/or negative) progressing from start up to but not including end.
[start=0](Number): The start of the range.end(Number): The end of the range.[step=1](Number): The value to increment or decrement by.
(Array): Returns a new range array.
_.range(10);
// => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
_.range(1, 11);
// => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
_.range(0, 30, 5);
// => [0, 5, 10, 15, 20, 25]
_.range(0, -10, -1);
// => [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
_.range(0);
// => []The opposite of _.initial, this method gets all but the first value of array. If a number n is passed, the first n values are excluded from the result. If a callback function is passed, elements at the beginning of the array are excluded from the result as long as the callback returns truthy. The callback is bound to thisArg and invoked with three arguments; (value, index, array).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
drop, tail
array(Array): The array to query.[callback|n=1](Function|Object|Number|String): The function called per element or the number of elements to exclude. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a slice of array.
_.rest([1, 2, 3]);
// => [2, 3]
_.rest([1, 2, 3], 2);
// => [3]
_.rest([1, 2, 3], function(num) {
return num < 3;
});
// => [3]
var food = [
{ 'name': 'banana', 'organic': true },
{ 'name': 'beet', 'organic': false },
];
// using "_.pluck" callback shorthand
_.rest(food, 'organic');
// => [{ 'name': 'beet', 'organic': false }]
var food = [
{ 'name': 'apple', 'type': 'fruit' },
{ 'name': 'banana', 'type': 'fruit' },
{ 'name': 'beet', 'type': 'vegetable' }
];
// using "_.where" callback shorthand
_.rest(food, { 'type': 'fruit' });
// => [{ 'name': 'beet', 'type': 'vegetable' }]Uses a binary search to determine the smallest index at which the value should be inserted into array in order to maintain the sort order of the sorted array. If callback is passed, it will be executed for value and each element in array to compute their sort ranking. The callback is bound to thisArg and invoked with one argument; (value).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
array(Array): The array to inspect.value(Mixed): The value to evaluate.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Number): Returns the index at which the value should be inserted into array.
_.sortedIndex([20, 30, 50], 40);
// => 2
// using "_.pluck" callback shorthand
_.sortedIndex([{ 'x': 20 }, { 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
// => 2
var dict = {
'wordToNumber': { 'twenty': 20, 'thirty': 30, 'fourty': 40, 'fifty': 50 }
};
_.sortedIndex(['twenty', 'thirty', 'fifty'], 'fourty', function(word) {
return dict.wordToNumber[word];
});
// => 2
_.sortedIndex(['twenty', 'thirty', 'fifty'], 'fourty', function(word) {
return this.wordToNumber[word];
}, dict);
// => 2Computes the union of the passed-in arrays using strict equality for comparisons, i.e. ===.
[array1, array2, ...](Array): Arrays to process.
(Array): Returns a new array of unique values, in order, that are present in one or more of the arrays.
_.union([1, 2, 3], [101, 2, 1, 10], [2, 1]);
// => [1, 2, 3, 101, 10]Creates a duplicate-value-free version of the array using strict equality for comparisons, i.e. ===. If the array is already sorted, passing true for isSorted will run a faster algorithm. If callback is passed, each element of array is passed through the callback before uniqueness is computed. The callback is bound to thisArg and invoked with three arguments; (value, index, array).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
unique
array(Array): The array to process.[isSorted=false](Boolean): A flag to indicate that thearrayis already sorted.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a duplicate-value-free array.
_.uniq([1, 2, 1, 3, 1]);
// => [1, 2, 3]
_.uniq([1, 1, 2, 2, 3], true);
// => [1, 2, 3]
_.uniq(['A', 'b', 'C', 'a', 'B', 'c'], function(letter) { return letter.toLowerCase(); });
// => ['A', 'b', 'C']
_.uniq([1, 2.5, 3, 1.5, 2, 3.5], function(num) { return this.floor(num); }, Math);
// => [1, 2.5, 3]
// using "_.pluck" callback shorthand
_.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 1 }, { 'x': 2 }]The inverse of _.zip, this method splits groups of elements into arrays composed of elements from each group at their corresponding indexes.
array(Array): The array to process.
(Array): Returns a new array of the composed arrays.
_.unzip([['moe', 30, true], ['larry', 40, false]]);
// => [['moe', 'larry'], [30, 40], [true, false]];Creates an array with all occurrences of the passed values removed using strict equality for comparisons, i.e. ===.
array(Array): The array to filter.[value1, value2, ...](Mixed): Values to remove.
(Array): Returns a new filtered array.
_.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
// => [2, 3, 4]Groups the elements of each array at their corresponding indexes. Useful for separate data sources that are coordinated through matching array indexes. For a matrix of nested arrays, _.zip.apply(...) can transpose the matrix in a similar fashion.
[array1, array2, ...](Array): Arrays to process.
(Array): Returns a new array of grouped elements.
_.zip(['moe', 'larry'], [30, 40], [true, false]);
// => [['moe', 30, true], ['larry', 40, false]]Creates an object composed from arrays of keys and values. Pass either a single two dimensional array, i.e. [[key1, value1], [key2, value2]], or two arrays, one of keys and one of corresponding values.
object
keys(Array): The array of keys.[values=[]](Array): The array of values.
(Object): Returns an object composed of the given keys and corresponding values.
_.zipObject(['moe', 'larry'], [30, 40]);
// => { 'moe': 30, 'larry': 40 }Creates a lodash object, which wraps the given value, to enable method chaining.
In addition to Lo-Dash methods, wrappers also have the following Array methods:
concat, join, pop, push, reverse, shift, slice, sort, splice, and unshift
Chaining is supported in custom builds as long as the value method is implicitly or explicitly included in the build.
The chainable wrapper functions are:
after, assign, bind, bindAll, bindKey, chain, compact, compose, concat, countBy, createCallback, debounce, defaults, defer, delay, difference, filter, flatten, forEach, forIn, forOwn, functions, groupBy, initial, intersection, invert, invoke, keys, map, max, memoize, merge, min, object, omit, once, pairs, partial, partialRight, pick, pluck, push, range, reject, rest, reverse, shuffle, slice, sort, sortBy, splice, tap, throttle, times, toArray, transform, union, uniq, unshift, unzip, values, where, without, wrap, and zip
The non-chainable wrapper functions are:
clone, cloneDeep, contains, escape, every, find, has, identity, indexOf, isArguments, isArray, isBoolean, isDate, isElement, isEmpty, isEqual, isFinite, isFunction, isNaN, isNull, isNumber, isObject, isPlainObject, isRegExp, isString, isUndefined, join, lastIndexOf, mixin, noConflict, parseInt, pop, random, reduce, reduceRight, result, shift, size, some, sortedIndex, runInContext, template, unescape, uniqueId, and value
The wrapper functions first and last return wrapped values when n is passed, otherwise they return unwrapped values.
chain
value(Mixed): The value to wrap in alodashinstance.
(Object): Returns a lodash instance.
var wrapped = _([1, 2, 3]);
// returns an unwrapped value
wrapped.reduce(function(sum, num) {
return sum + num;
});
// => 6
// returns a wrapped value
var squares = wrapped.map(function(num) {
return num * num;
});
_.isArray(squares);
// => false
_.isArray(squares.value());
// => trueInvokes interceptor with the value as the first argument, and then returns value. The purpose of this method is to "tap into" a method chain, in order to perform operations on intermediate results within the chain.
value(Mixed): The value to pass tointerceptor.interceptor(Function): The function to invoke.
(Mixed): Returns value.
_([1, 2, 3, 4])
.filter(function(num) { return num % 2 == 0; })
.tap(alert)
.map(function(num) { return num * num; })
.value();
// => // [2, 4] (alerted)
// => [4, 16]Produces the toString result of the wrapped value.
(String): Returns the string result.
_([1, 2, 3]).toString();
// => '1,2,3'Extracts the wrapped value.
value
(Mixed): Returns the wrapped value.
_([1, 2, 3]).valueOf();
// => [1, 2, 3]Creates an array of elements from the specified indexes, or keys, of the collection. Indexes may be specified as individual arguments or as arrays of indexes.
collection(Array|Object|String): The collection to iterate over.[index1, index2, ...](Array|Number|String): The indexes ofcollectionto retrieve, either as individual arguments or arrays.
(Array): Returns a new array of elements corresponding to the provided indexes.
_.at(['a', 'b', 'c', 'd', 'e'], [0, 2, 4]);
// => ['a', 'c', 'e']
_.at(['moe', 'larry', 'curly'], 0, 2);
// => ['moe', 'curly']Checks if a given target element is present in a collection using strict equality for comparisons, i.e. ===. If fromIndex is negative, it is used as the offset from the end of the collection.
include
collection(Array|Object|String): The collection to iterate over.target(Mixed): The value to check for.[fromIndex=0](Number): The index to search from.
(Boolean): Returns true if the target element is found, else false.
_.contains([1, 2, 3], 1);
// => true
_.contains([1, 2, 3], 1, 2);
// => false
_.contains({ 'name': 'moe', 'age': 40 }, 'moe');
// => true
_.contains('curly', 'ur');
// => trueCreates an object composed of keys returned from running each element of the collection through the given callback. The corresponding value of each key is the number of times the key was returned by the callback. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Object): Returns the composed aggregate object.
_.countBy([4.3, 6.1, 6.4], function(num) { return Math.floor(num); });
// => { '4': 1, '6': 2 }
_.countBy([4.3, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
// => { '4': 1, '6': 2 }
_.countBy(['one', 'two', 'three'], 'length');
// => { '3': 2, '5': 1 }Checks if the callback returns a truthy value for all elements of a collection. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
all
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Boolean): Returns true if all elements pass the callback check, else false.
_.every([true, 1, null, 'yes'], Boolean);
// => false
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
// using "_.pluck" callback shorthand
_.every(stooges, 'age');
// => true
// using "_.where" callback shorthand
_.every(stooges, { 'age': 50 });
// => falseExamines each element in a collection, returning an array of all elements the callback returns truthy for. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
select
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a new array of elements that passed the callback check.
var evens = _.filter([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
// => [2, 4, 6]
var food = [
{ 'name': 'apple', 'organic': false, 'type': 'fruit' },
{ 'name': 'carrot', 'organic': true, 'type': 'vegetable' }
];
// using "_.pluck" callback shorthand
_.filter(food, 'organic');
// => [{ 'name': 'carrot', 'organic': true, 'type': 'vegetable' }]
// using "_.where" callback shorthand
_.filter(food, { 'type': 'fruit' });
// => [{ 'name': 'apple', 'organic': false, 'type': 'fruit' }]Examines each element in a collection, returning the first that the callback returns truthy for. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
detect, findWhere
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the found element, else undefined.
_.find([1, 2, 3, 4], function(num) {
return num % 2 == 0;
});
// => 2
var food = [
{ 'name': 'apple', 'organic': false, 'type': 'fruit' },
{ 'name': 'banana', 'organic': true, 'type': 'fruit' },
{ 'name': 'beet', 'organic': false, 'type': 'vegetable' }
];
// using "_.where" callback shorthand
_.find(food, { 'type': 'vegetable' });
// => { 'name': 'beet', 'organic': false, 'type': 'vegetable' }
// using "_.pluck" callback shorthand
_.find(food, 'organic');
// => { 'name': 'banana', 'organic': true, 'type': 'fruit' }Iterates over a collection, executing the callback for each element in the collection. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection). Callbacks may exit iteration early by explicitly returning false.
each
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function): The function called per iteration.[thisArg](Mixed): Thethisbinding ofcallback.
(Array, Object, String): Returns collection.
_([1, 2, 3]).forEach(alert).join(',');
// => alerts each number and returns '1,2,3'
_.forEach({ 'one': 1, 'two': 2, 'three': 3 }, alert);
// => alerts each number value (order is not guaranteed)Creates an object composed of keys returned from running each element of the collection through the callback. The corresponding value of each key is an array of elements passed to callback that returned the key. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Object): Returns the composed aggregate object.
_.groupBy([4.2, 6.1, 6.4], function(num) { return Math.floor(num); });
// => { '4': [4.2], '6': [6.1, 6.4] }
_.groupBy([4.2, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
// => { '4': [4.2], '6': [6.1, 6.4] }
// using "_.pluck" callback shorthand
_.groupBy(['one', 'two', 'three'], 'length');
// => { '3': ['one', 'two'], '5': ['three'] }Invokes the method named by methodName on each element in the collection, returning an array of the results of each invoked method. Additional arguments will be passed to each invoked method. If methodName is a function, it will be invoked for, and this bound to, each element in the collection.
collection(Array|Object|String): The collection to iterate over.methodName(Function|String): The name of the method to invoke or the function invoked per iteration.[arg1, arg2, ...](Mixed): Arguments to invoke the method with.
(Array): Returns a new array of the results of each invoked method.
_.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
// => [[1, 5, 7], [1, 2, 3]]
_.invoke([123, 456], String.prototype.split, '');
// => [['1', '2', '3'], ['4', '5', '6']]Creates an array of values by running each element in the collection through the callback. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
collect
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a new array of the results of each callback execution.
_.map([1, 2, 3], function(num) { return num * 3; });
// => [3, 6, 9]
_.map({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { return num * 3; });
// => [3, 6, 9] (order is not guaranteed)
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
// using "_.pluck" callback shorthand
_.map(stooges, 'name');
// => ['moe', 'larry']Retrieves the maximum value of an array. If callback is passed, it will be executed for each value in the array to generate the criterion by which the value is ranked. The callback is bound to thisArg and invoked with three arguments; (value, index, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the maximum value.
_.max([4, 2, 8, 6]);
// => 8
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
_.max(stooges, function(stooge) { return stooge.age; });
// => { 'name': 'larry', 'age': 50 };
// using "_.pluck" callback shorthand
_.max(stooges, 'age');
// => { 'name': 'larry', 'age': 50 };Retrieves the minimum value of an array. If callback is passed, it will be executed for each value in the array to generate the criterion by which the value is ranked. The callback is bound to thisArg and invoked with three arguments; (value, index, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the minimum value.
_.min([4, 2, 8, 6]);
// => 2
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
_.min(stooges, function(stooge) { return stooge.age; });
// => { 'name': 'moe', 'age': 40 };
// using "_.pluck" callback shorthand
_.min(stooges, 'age');
// => { 'name': 'moe', 'age': 40 };Retrieves the value of a specified property from all elements in the collection.
collection(Array|Object|String): The collection to iterate over.property(String): The property to pluck.
(Array): Returns a new array of property values.
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
_.pluck(stooges, 'name');
// => ['moe', 'larry']Reduces a collection to a value which is the accumulated result of running each element in the collection through the callback, where each successive callback execution consumes the return value of the previous execution. If accumulator is not passed, the first element of the collection will be used as the initial accumulator value. The callback is bound to thisArg and invoked with four arguments; (accumulator, value, index|key, collection).
foldl, inject
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function): The function called per iteration.[accumulator](Mixed): Initial value of the accumulator.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the accumulated value.
var sum = _.reduce([1, 2, 3], function(sum, num) {
return sum + num;
});
// => 6
var mapped = _.reduce({ 'a': 1, 'b': 2, 'c': 3 }, function(result, num, key) {
result[key] = num * 3;
return result;
}, {});
// => { 'a': 3, 'b': 6, 'c': 9 }This method is similar to _.reduce, except that it iterates over a collection from right to left.
foldr
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function): The function called per iteration.[accumulator](Mixed): Initial value of the accumulator.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the accumulated value.
var list = [[0, 1], [2, 3], [4, 5]];
var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
// => [4, 5, 2, 3, 0, 1]The opposite of _.filter, this method returns the elements of a collection that callback does not return truthy for.
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a new array of elements that did not pass the callback check.
var odds = _.reject([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
// => [1, 3, 5]
var food = [
{ 'name': 'apple', 'organic': false, 'type': 'fruit' },
{ 'name': 'carrot', 'organic': true, 'type': 'vegetable' }
];
// using "_.pluck" callback shorthand
_.reject(food, 'organic');
// => [{ 'name': 'apple', 'organic': false, 'type': 'fruit' }]
// using "_.where" callback shorthand
_.reject(food, { 'type': 'fruit' });
// => [{ 'name': 'carrot', 'organic': true, 'type': 'vegetable' }]Creates an array of shuffled array values, using a version of the Fisher-Yates shuffle. See http://en.wikipedia.org/wiki/Fisher-Yates_shuffle.
collection(Array|Object|String): The collection to shuffle.
(Array): Returns a new shuffled collection.
_.shuffle([1, 2, 3, 4, 5, 6]);
// => [4, 1, 6, 3, 5, 2]Gets the size of the collection by returning collection.length for arrays and array-like objects or the number of own enumerable properties for objects.
collection(Array|Object|String): The collection to inspect.
(Number): Returns collection.length or number of own enumerable properties.
_.size([1, 2]);
// => 2
_.size({ 'one': 1, 'two': 2, 'three': 3 });
// => 3
_.size('curly');
// => 5Checks if the callback returns a truthy value for any element of a collection. The function returns as soon as it finds passing value, and does not iterate over the entire collection. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
any
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Boolean): Returns true if any element passes the callback check, else false.
_.some([null, 0, 'yes', false], Boolean);
// => true
var food = [
{ 'name': 'apple', 'organic': false, 'type': 'fruit' },
{ 'name': 'carrot', 'organic': true, 'type': 'vegetable' }
];
// using "_.pluck" callback shorthand
_.some(food, 'organic');
// => true
// using "_.where" callback shorthand
_.some(food, { 'type': 'meat' });
// => falseCreates an array of elements, sorted in ascending order by the results of running each element in the collection through the callback. This method performs a stable sort, that is, it will preserve the original sort order of equal elements. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection).
If a property name is passed for callback, the created "_.pluck" style callback will return the property value of the given element.
If an object is passed for callback, the created "_.where" style callback will return true for elements that have the properties of the given object, else false.
collection(Array|Object|String): The collection to iterate over.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a new array of sorted elements.
_.sortBy([1, 2, 3], function(num) { return Math.sin(num); });
// => [3, 1, 2]
_.sortBy([1, 2, 3], function(num) { return this.sin(num); }, Math);
// => [3, 1, 2]
// using "_.pluck" callback shorthand
_.sortBy(['banana', 'strawberry', 'apple'], 'length');
// => ['apple', 'banana', 'strawberry']Converts the collection to an array.
collection(Array|Object|String): The collection to convert.
(Array): Returns the new converted array.
(function() { return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
// => [2, 3, 4]Examines each element in a collection, returning an array of all elements that have the given properties. When checking properties, this method performs a deep comparison between values to determine if they are equivalent to each other.
collection(Array|Object|String): The collection to iterate over.properties(Object): The object of property values to filter by.
(Array): Returns a new array of elements that have the given properties.
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
_.where(stooges, { 'age': 40 });
// => [{ 'name': 'moe', 'age': 40 }]If n is greater than 0, a function is created that is restricted to executing func, with the this binding and arguments of the created function, only after it is called n times. If n is less than 1, func is executed immediately, without a this binding or additional arguments, and its result is returned.
n(Number): The number of times the function must be called before it is executed.func(Function): The function to restrict.
(Function): Returns the new restricted function.
var renderNotes = _.after(notes.length, render);
_.forEach(notes, function(note) {
note.asyncSave({ 'success': renderNotes });
});
// `renderNotes` is run once, after all notes have savedCreates a function that, when called, invokes func with the this binding of thisArg and prepends any additional bind arguments to those passed to the bound function.
func(Function): The function to bind.[thisArg](Mixed): Thethisbinding offunc.[arg1, arg2, ...](Mixed): Arguments to be partially applied.
(Function): Returns the new bound function.
var func = function(greeting) {
return greeting + ' ' + this.name;
};
func = _.bind(func, { 'name': 'moe' }, 'hi');
func();
// => 'hi moe'Binds methods on object to object, overwriting the existing method. Method names may be specified as individual arguments or as arrays of method names. If no method names are provided, all the function properties of object will be bound.
object(Object): The object to bind and assign the bound methods to.[methodName1, methodName2, ...](String): Method names on the object to bind.
(Object): Returns object.
var view = {
'label': 'docs',
'onClick': function() { alert('clicked ' + this.label); }
};
_.bindAll(view);
jQuery('#docs').on('click', view.onClick);
// => alerts 'clicked docs', when the button is clickedCreates a function that, when called, invokes the method at object[key] and prepends any additional bindKey arguments to those passed to the bound function. This method differs from _.bind by allowing bound functions to reference methods that will be redefined or don't yet exist. See http://michaux.ca/articles/lazy-function-definition-pattern.
object(Object): The object the method belongs to.key(String): The key of the method.[arg1, arg2, ...](Mixed): Arguments to be partially applied.
(Function): Returns the new bound function.
var object = {
'name': 'moe',
'greet': function(greeting) {
return greeting + ' ' + this.name;
}
};
var func = _.bindKey(object, 'greet', 'hi');
func();
// => 'hi moe'
object.greet = function(greeting) {
return greeting + ', ' + this.name + '!';
};
func();
// => 'hi, moe!'Creates a function that is the composition of the passed functions, where each function consumes the return value of the function that follows. For example, composing the functions f(), g(), and h() produces f(g(h())). Each function is executed with the this binding of the composed function.
[func1, func2, ...](Function): Functions to compose.
(Function): Returns the new composed function.
var greet = function(name) { return 'hi ' + name; };
var exclaim = function(statement) { return statement + '!'; };
var welcome = _.compose(exclaim, greet);
welcome('moe');
// => 'hi moe!'Produces a callback bound to an optional thisArg. If func is a property name, the created callback will return the property value for a given element. If func is an object, the created callback will return true for elements that contain the equivalent object properties, otherwise it will return false.
Note: All Lo-Dash methods, that accept a callback argument, use _.createCallback.
[func=identity](Mixed): The value to convert to a callback.[thisArg](Mixed): Thethisbinding of the created callback.[argCount=3](Number): The number of arguments the callback accepts.
(Function): Returns a callback function.
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
// wrap to create custom callback shorthands
_.createCallback = _.wrap(_.createCallback, function(func, callback, thisArg) {
var match = /^(.+?)__([gl]t)(.+)$/.exec(callback);
return !match ? func(callback, thisArg) : function(object) {
return match[2] == 'gt' ? object[match[1]] > match[3] : object[match[1]] < match[3];
};
});
_.filter(stooges, 'age__gt45');
// => [{ 'name': 'larry', 'age': 50 }]
// create mixins with support for "_.pluck" and "_.where" callback shorthands
_.mixin({
'toLookup': function(collection, callback, thisArg) {
callback = _.createCallback(callback, thisArg);
return _.reduce(collection, function(result, value, index, collection) {
return (result[callback(value, index, collection)] = value, result);
}, {});
}
});
_.toLookup(stooges, 'name');
// => { 'moe': { 'name': 'moe', 'age': 40 }, 'larry': { 'name': 'larry', 'age': 50 } }Creates a function that will delay the execution of func until after wait milliseconds have elapsed since the last time it was invoked. Pass an options object to indicate that func should be invoked on the leading and/or trailing edge of the wait timeout. Subsequent calls to the debounced function will return the result of the last func call.
Note: If leading and trailing options are true, func will be called on the trailing edge of the timeout only if the the debounced function is invoked more than once during the wait timeout.
func(Function): The function to debounce.wait(Number): The number of milliseconds to delay.options(Object): The options object. [leading=false] A boolean to specify execution on the leading edge of the timeout. [maxWait] The maximum timefuncis allowed to be delayed before it's called. [trailing=true] A boolean to specify execution on the trailing edge of the timeout.
(Function): Returns the new debounced function.
var lazyLayout = _.debounce(calculateLayout, 300);
jQuery(window).on('resize', lazyLayout);
jQuery('#postbox').on('click', _.debounce(sendMail, 200, {
'leading': true,
'trailing': false
});Defers executing the func function until the current call stack has cleared. Additional arguments will be passed to func when it is invoked.
func(Function): The function to defer.[arg1, arg2, ...](Mixed): Arguments to invoke the function with.
(Number): Returns the timer id.
_.defer(function() { alert('deferred'); });
// returns from the function before `alert` is calledExecutes the func function after wait milliseconds. Additional arguments will be passed to func when it is invoked.
func(Function): The function to delay.wait(Number): The number of milliseconds to delay execution.[arg1, arg2, ...](Mixed): Arguments to invoke the function with.
(Number): Returns the timer id.
var log = _.bind(console.log, console);
_.delay(log, 1000, 'logged later');
// => 'logged later' (Appears after one second.)Creates a function that memoizes the result of func. If resolver is passed, it will be used to determine the cache key for storing the result based on the arguments passed to the memoized function. By default, the first argument passed to the memoized function is used as the cache key. The func is executed with the this binding of the memoized function. The result cache is exposed as the cache property on the memoized function.
func(Function): The function to have its output memoized.[resolver](Function): A function used to resolve the cache key.
(Function): Returns the new memoizing function.
var fibonacci = _.memoize(function(n) {
return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
});Creates a function that is restricted to execute func once. Repeat calls to the function will return the value of the first call. The func is executed with the this binding of the created function.
func(Function): The function to restrict.
(Function): Returns the new restricted function.
var initialize = _.once(createApplication);
initialize();
initialize();
// `initialize` executes `createApplication` onceCreates a function that, when called, invokes func with any additional partial arguments prepended to those passed to the new function. This method is similar to _.bind, except it does not alter the this binding.
func(Function): The function to partially apply arguments to.[arg1, arg2, ...](Mixed): Arguments to be partially applied.
(Function): Returns the new partially applied function.
var greet = function(greeting, name) { return greeting + ' ' + name; };
var hi = _.partial(greet, 'hi');
hi('moe');
// => 'hi moe'This method is similar to _.partial, except that partial arguments are appended to those passed to the new function.
func(Function): The function to partially apply arguments to.[arg1, arg2, ...](Mixed): Arguments to be partially applied.
(Function): Returns the new partially applied function.
var defaultsDeep = _.partialRight(_.merge, _.defaults);
var options = {
'variable': 'data',
'imports': { 'jq': $ }
};
defaultsDeep(options, _.templateSettings);
options.variable
// => 'data'
options.imports
// => { '_': _, 'jq': $ }Creates a function that, when executed, will only call the func function at most once per every wait milliseconds. Pass an options object to indicate that func should be invoked on the leading and/or trailing edge of the wait timeout. Subsequent calls to the throttled function will return the result of the last func call.
Note: If leading and trailing options are true, func will be called on the trailing edge of the timeout only if the the throttled function is invoked more than once during the wait timeout.
func(Function): The function to throttle.wait(Number): The number of milliseconds to throttle executions to.options(Object): The options object. [leading=true] A boolean to specify execution on the leading edge of the timeout. [trailing=true] A boolean to specify execution on the trailing edge of the timeout.
(Function): Returns the new throttled function.
var throttled = _.throttle(updatePosition, 100);
jQuery(window).on('scroll', throttled);
jQuery('.interactive').on('click', _.throttle(renewToken, 300000, {
'trailing': false
}));Creates a function that passes value to the wrapper function as its first argument. Additional arguments passed to the function are appended to those passed to the wrapper function. The wrapper is executed with the this binding of the created function.
value(Mixed): The value to wrap.wrapper(Function): The wrapper function.
(Function): Returns the new function.
var hello = function(name) { return 'hello ' + name; };
hello = _.wrap(hello, function(func) {
return 'before, ' + func('moe') + ', after';
});
hello();
// => 'before, hello moe, after'Assigns own enumerable properties of source object(s) to the destination object. Subsequent sources will overwrite property assignments of previous sources. If a callback function is passed, it will be executed to produce the assigned values. The callback is bound to thisArg and invoked with two arguments; (objectValue, sourceValue).
extend
object(Object): The destination object.[source1, source2, ...](Object): The source objects.[callback](Function): The function to customize assigning values.[thisArg](Mixed): Thethisbinding ofcallback.
(Object): Returns the destination object.
_.assign({ 'name': 'moe' }, { 'age': 40 });
// => { 'name': 'moe', 'age': 40 }
var defaults = _.partialRight(_.assign, function(a, b) {
return typeof a == 'undefined' ? b : a;
});
var food = { 'name': 'apple' };
defaults(food, { 'name': 'banana', 'type': 'fruit' });
// => { 'name': 'apple', 'type': 'fruit' }Creates a clone of value. If deep is true, nested objects will also be cloned, otherwise they will be assigned by reference. If a callback function is passed, it will be executed to produce the cloned values. If callback returns undefined, cloning will be handled by the method instead. The callback is bound to thisArg and invoked with one argument; (value).
value(Mixed): The value to clone.[deep=false](Boolean): A flag to indicate a deep clone.[callback](Function): The function to customize cloning values.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the cloned value.
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
var shallow = _.clone(stooges);
shallow[0] === stooges[0];
// => true
var deep = _.clone(stooges, true);
deep[0] === stooges[0];
// => false
_.mixin({
'clone': _.partialRight(_.clone, function(value) {
return _.isElement(value) ? value.cloneNode(false) : undefined;
})
});
var clone = _.clone(document.body);
clone.childNodes.length;
// => 0Creates a deep clone of value. If a callback function is passed, it will be executed to produce the cloned values. If callback returns undefined, cloning will be handled by the method instead. The callback is bound to thisArg and invoked with one argument; (value).
Note: This method is loosely based on the structured clone algorithm. Functions and DOM nodes are not cloned. The enumerable properties of arguments objects and objects created by constructors other than Object are cloned to plain Object objects. See http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm.
value(Mixed): The value to deep clone.[callback](Function): The function to customize cloning values.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the deep cloned value.
var stooges = [
{ 'name': 'moe', 'age': 40 },
{ 'name': 'larry', 'age': 50 }
];
var deep = _.cloneDeep(stooges);
deep[0] === stooges[0];
// => false
var view = {
'label': 'docs',
'node': element
};
var clone = _.cloneDeep(view, function(value) {
return _.isElement(value) ? value.cloneNode(true) : undefined;
});
clone.node == view.node;
// => falseAssigns own enumerable properties of source object(s) to the destination object for all destination properties that resolve to undefined. Once a property is set, additional defaults of the same property will be ignored.
object(Object): The destination object.[source1, source2, ...](Object): The source objects.
(Object): Returns the destination object.
var food = { 'name': 'apple' };
_.defaults(food, { 'name': 'banana', 'type': 'fruit' });
// => { 'name': 'apple', 'type': 'fruit' }This method is similar to _.find, except that it returns the key of the element that passes the callback check, instead of the element itself.
object(Object): The object to search.[callback=identity](Function|Object|String): The function called per iteration. If a property name or object is passed, it will be used to create a ".pluck" or ".where" style callback, respectively.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the key of the found element, else undefined.
_.findKey({ 'a': 1, 'b': 2, 'c': 3, 'd': 4 }, function(num) {
return num % 2 == 0;
});
// => 'b'Iterates over object's own and inherited enumerable properties, executing the callback for each property. The callback is bound to thisArg and invoked with three arguments; (value, key, object). Callbacks may exit iteration early by explicitly returning false.
object(Object): The object to iterate over.[callback=identity](Function): The function called per iteration.[thisArg](Mixed): Thethisbinding ofcallback.
(Object): Returns object.
function Dog(name) {
this.name = name;
}
Dog.prototype.bark = function() {
alert('Woof, woof!');
};
_.forIn(new Dog('Dagny'), function(value, key) {
alert(key);
});
// => alerts 'name' and 'bark' (order is not guaranteed)Iterates over an object's own enumerable properties, executing the callback for each property. The callback is bound to thisArg and invoked with three arguments; (value, key, object). Callbacks may exit iteration early by explicitly returning false.
object(Object): The object to iterate over.[callback=identity](Function): The function called per iteration.[thisArg](Mixed): Thethisbinding ofcallback.
(Object): Returns object.
_.forOwn({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
alert(key);
});
// => alerts '0', '1', and 'length' (order is not guaranteed)Creates a sorted array of all enumerable properties, own and inherited, of object that have function values.
methods
object(Object): The object to inspect.
(Array): Returns a new array of property names that have function values.
_.functions(_);
// => ['all', 'any', 'bind', 'bindAll', 'clone', 'compact', 'compose', ...]Checks if the specified object property exists and is a direct property, instead of an inherited property.
object(Object): The object to check.property(String): The property to check for.
(Boolean): Returns true if key is a direct property, else false.
_.has({ 'a': 1, 'b': 2, 'c': 3 }, 'b');
// => trueCreates an object composed of the inverted keys and values of the given object.
object(Object): The object to invert.
(Object): Returns the created inverted object.
_.invert({ 'first': 'moe', 'second': 'larry' });
// => { 'moe': 'first', 'larry': 'second' }Checks if value is an arguments object.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is an arguments object, else false.
(function() { return _.isArguments(arguments); })(1, 2, 3);
// => true
_.isArguments([1, 2, 3]);
// => falseChecks if value is an array.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is an array, else false.
(function() { return _.isArray(arguments); })();
// => false
_.isArray([1, 2, 3]);
// => trueChecks if value is a boolean value.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is a boolean value, else false.
_.isBoolean(null);
// => falseChecks if value is a date.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is a date, else false.
_.isDate(new Date);
// => trueChecks if value is a DOM element.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is a DOM element, else false.
_.isElement(document.body);
// => trueChecks if value is empty. Arrays, strings, or arguments objects with a length of 0 and objects with no own enumerable properties are considered "empty".
value(Array|Object|String): The value to inspect.
(Boolean): Returns true, if the value is empty, else false.
_.isEmpty([1, 2, 3]);
// => false
_.isEmpty({});
// => true
_.isEmpty('');
// => truePerforms a deep comparison between two values to determine if they are equivalent to each other. If callback is passed, it will be executed to compare values. If callback returns undefined, comparisons will be handled by the method instead. The callback is bound to thisArg and invoked with two arguments; (a, b).
a(Mixed): The value to compare.b(Mixed): The other value to compare.[callback](Function): The function to customize comparing values.[thisArg](Mixed): Thethisbinding ofcallback.
(Boolean): Returns true, if the values are equivalent, else false.
var moe = { 'name': 'moe', 'age': 40 };
var copy = { 'name': 'moe', 'age': 40 };
moe == copy;
// => false
_.isEqual(moe, copy);
// => true
var words = ['hello', 'goodbye'];
var otherWords = ['hi', 'goodbye'];
_.isEqual(words, otherWords, function(a, b) {
var reGreet = /^(?:hello|hi)$/i,
aGreet = _.isString(a) && reGreet.test(a),
bGreet = _.isString(b) && reGreet.test(b);
return (aGreet || bGreet) ? (aGreet == bGreet) : undefined;
});
// => trueChecks if value is, or can be coerced to, a finite number.
Note: This is not the same as native isFinite, which will return true for booleans and empty strings. See http://es5.github.com/#x15.1.2.5.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is finite, else false.
_.isFinite(-101);
// => true
_.isFinite('10');
// => true
_.isFinite(true);
// => false
_.isFinite('');
// => false
_.isFinite(Infinity);
// => falseChecks if value is a function.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is a function, else false.
_.isFunction(_);
// => trueChecks if value is NaN.
Note: This is not the same as native isNaN, which will return true for undefined and other values. See http://es5.github.com/#x15.1.2.4.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is NaN, else false.
_.isNaN(NaN);
// => true
_.isNaN(new Number(NaN));
// => true
isNaN(undefined);
// => true
_.isNaN(undefined);
// => falseChecks if value is null.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is null, else false.
_.isNull(null);
// => true
_.isNull(undefined);
// => falseChecks if value is a number.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is a number, else false.
_.isNumber(8.4 * 5);
// => trueChecks if value is the language type of Object. (e.g. arrays, functions, objects, regexes, new Number(0), and new String(''))
value(Mixed): The value to check.
(Boolean): Returns true, if the value is an object, else false.
_.isObject({});
// => true
_.isObject([1, 2, 3]);
// => true
_.isObject(1);
// => falseChecks if a given value is an object created by the Object constructor.
value(Mixed): The value to check.
(Boolean): Returns true, if value is a plain object, else false.
function Stooge(name, age) {
this.name = name;
this.age = age;
}
_.isPlainObject(new Stooge('moe', 40));
// => false
_.isPlainObject([1, 2, 3]);
// => false
_.isPlainObject({ 'name': 'moe', 'age': 40 });
// => trueChecks if value is a regular expression.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is a regular expression, else false.
_.isRegExp(/moe/);
// => trueChecks if value is a string.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is a string, else false.
_.isString('moe');
// => trueChecks if value is undefined.
value(Mixed): The value to check.
(Boolean): Returns true, if the value is undefined, else false.
_.isUndefined(void 0);
// => trueCreates an array composed of the own enumerable property names of object.
object(Object): The object to inspect.
(Array): Returns a new array of property names.
_.keys({ 'one': 1, 'two': 2, 'three': 3 });
// => ['one', 'two', 'three'] (order is not guaranteed)Recursively merges own enumerable properties of the source object(s), that don't resolve to undefined, into the destination object. Subsequent sources will overwrite property assignments of previous sources. If a callback function is passed, it will be executed to produce the merged values of the destination and source properties. If callback returns undefined, merging will be handled by the method instead. The callback is bound to thisArg and invoked with two arguments; (objectValue, sourceValue).
object(Object): The destination object.[source1, source2, ...](Object): The source objects.[callback](Function): The function to customize merging properties.[thisArg](Mixed): Thethisbinding ofcallback.
(Object): Returns the destination object.
var names = {
'stooges': [
{ 'name': 'moe' },
{ 'name': 'larry' }
]
};
var ages = {
'stooges': [
{ 'age': 40 },
{ 'age': 50 }
]
};
_.merge(names, ages);
// => { 'stooges': [{ 'name': 'moe', 'age': 40 }, { 'name': 'larry', 'age': 50 }] }
var food = {
'fruits': ['apple'],
'vegetables': ['beet']
};
var otherFood = {
'fruits': ['banana'],
'vegetables': ['carrot']
};
_.merge(food, otherFood, function(a, b) {
return _.isArray(a) ? a.concat(b) : undefined;
});
// => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot] }Creates a shallow clone of object excluding the specified properties. Property names may be specified as individual arguments or as arrays of property names. If a callback function is passed, it will be executed for each property in the object, omitting the properties callback returns truthy for. The callback is bound to thisArg and invoked with three arguments; (value, key, object).
object(Object): The source object.callback|[prop1, prop2, ...](Function|String): The properties to omit or the function called per iteration.[thisArg](Mixed): Thethisbinding ofcallback.
(Object): Returns an object without the omitted properties.
_.omit({ 'name': 'moe', 'age': 40 }, 'age');
// => { 'name': 'moe' }
_.omit({ 'name': 'moe', 'age': 40 }, function(value) {
return typeof value == 'number';
});
// => { 'name': 'moe' }Creates a two dimensional array of the given object's key-value pairs, i.e. [[key1, value1], [key2, value2]].
object(Object): The object to inspect.
(Array): Returns new array of key-value pairs.
_.pairs({ 'moe': 30, 'larry': 40 });
// => [['moe', 30], ['larry', 40]] (order is not guaranteed)Creates a shallow clone of object composed of the specified properties. Property names may be specified as individual arguments or as arrays of property names. If callback is passed, it will be executed for each property in the object, picking the properties callback returns truthy for. The callback is bound to thisArg and invoked with three arguments; (value, key, object).
object(Object): The source object.callback|[prop1, prop2, ...](Array|Function|String): The function called per iteration or properties to pick, either as individual arguments or arrays.[thisArg](Mixed): Thethisbinding ofcallback.
(Object): Returns an object composed of the picked properties.
_.pick({ 'name': 'moe', '_userid': 'moe1' }, 'name');
// => { 'name': 'moe' }
_.pick({ 'name': 'moe', '_userid': 'moe1' }, function(value, key) {
return key.charAt(0) != '_';
});
// => { 'name': 'moe' }An alternative to _.reduce, this method transforms an object to a new accumulator object which is the result of running each of its elements through the callback, with each callback execution potentially mutating the accumulator object. The callback is bound to thisArg and invoked with four arguments; (accumulator, value, key, object). Callbacks may exit iteration early by explicitly returning false.
collection(Array|Object): The collection to iterate over.[callback=identity](Function): The function called per iteration.[accumulator](Mixed): The custom accumulator value.[thisArg](Mixed): Thethisbinding ofcallback.
(Mixed): Returns the accumulated value.
var squares = _.transform([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], function(result, num) {
num *= num;
if (num % 2) {
return result.push(num) < 3;
}
});
// => [1, 9, 25]
var mapped = _.transform({ 'a': 1, 'b': 2, 'c': 3 }, function(result, num, key) {
result[key] = num * 3;
});
// => { 'a': 3, 'b': 6, 'c': 9 }Creates an array composed of the own enumerable property values of object.
object(Object): The object to inspect.
(Array): Returns a new array of property values.
_.values({ 'one': 1, 'two': 2, 'three': 3 });
// => [1, 2, 3] (order is not guaranteed)Converts the characters &, <, >, ", and ' in string to their corresponding HTML entities.
string(String): The string to escape.
(String): Returns the escaped string.
_.escape('Moe, Larry & Curly');
// => 'Moe, Larry & Curly'This method returns the first argument passed to it.
value(Mixed): Any value.
(Mixed): Returns value.
var moe = { 'name': 'moe' };
moe === _.identity(moe);
// => trueAdds functions properties of object to the lodash function and chainable wrapper.
object(Object): The object of function properties to add tolodash.
_.mixin({
'capitalize': function(string) {
return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
}
});
_.capitalize('moe');
// => 'Moe'
_('moe').capitalize();
// => 'Moe'Reverts the '_' variable to its previous value and returns a reference to the lodash function.
(Function): Returns the lodash function.
var lodash = _.noConflict();Converts the given value into an integer of the specified radix. If radix is undefined or 0, a radix of 10 is used unless the value is a hexadecimal, in which case a radix of 16 is used.
Note: This method avoids differences in native ES3 and ES5 parseInt implementations. See http://es5.github.com/#E.
value(String): The value to parse.[radix](Number): The radix used to interpret the value to parse.
(Number): Returns the new integer value.
_.parseInt('08');
// => 8Produces a random number between min and max (inclusive). If only one argument is passed, a number between 0 and the given number will be returned.
[min=0](Number): The minimum possible value.[max=1](Number): The maximum possible value.
(Number): Returns a random number.
_.random(0, 5);
// => a number between 0 and 5
_.random(5);
// => also a number between 0 and 5Resolves the value of property on object. If property is a function, it will be invoked with the this binding of object and its result returned, else the property value is returned. If object is falsey, then undefined is returned.
object(Object): The object to inspect.property(String): The property to get the value of.
(Mixed): Returns the resolved value.
var object = {
'cheese': 'crumpets',
'stuff': function() {
return 'nonsense';
}
};
_.result(object, 'cheese');
// => 'crumpets'
_.result(object, 'stuff');
// => 'nonsense'Create a new lodash function using the given context object.
[context=window](Object): The context object.
(Function): Returns the lodash function.
A micro-templating method that handles arbitrary delimiters, preserves whitespace, and correctly escapes quotes within interpolated code.
Note: In the development build, _.template utilizes sourceURLs for easier debugging. See http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
For more information on precompiling templates see:
http://lodash.com/#custom-builds
For more information on Chrome extension sandboxes see:
http://developer.chrome.com/stable/extensions/sandboxingEval.html
text(String): The template text.data(Object): The data object used to populate the text.options(Object): The options object. escape - The "escape" delimiter regexp. evaluate - The "evaluate" delimiter regexp. interpolate - The "interpolate" delimiter regexp. sourceURL - The sourceURL of the template's compiled source. variable - The data object variable name.
(Function, String): Returns a compiled function when no data object is given, else it returns the interpolated text.
// using a compiled template
var compiled = _.template('hello <%= name %>');
compiled({ 'name': 'moe' });
// => 'hello moe'
var list = '<% _.forEach(people, function(name) { %><li><%= name %></li><% }); %>';
_.template(list, { 'people': ['moe', 'larry'] });
// => '<li>moe</li><li>larry</li>'
// using the "escape" delimiter to escape HTML in data property values
_.template('<b><%- value %></b>', { 'value': '<script>' });
// => '<b><script></b>'
// using the ES6 delimiter as an alternative to the default "interpolate" delimiter
_.template('hello ${ name }', { 'name': 'curly' });
// => 'hello curly'
// using the internal `print` function in "evaluate" delimiters
_.template('<% print("hello " + epithet); %>!', { 'epithet': 'stooge' });
// => 'hello stooge!'
// using custom template delimiters
_.templateSettings = {
'interpolate': /{{([\s\S]+?)}}/g
};
_.template('hello {{ name }}!', { 'name': 'mustache' });
// => 'hello mustache!'
// using the `sourceURL` option to specify a custom sourceURL for the template
var compiled = _.template('hello <%= name %>', null, { 'sourceURL': '/basic/greeting.jst' });
compiled(data);
// => find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector
// using the `variable` option to ensure a with-statement isn't used in the compiled template
var compiled = _.template('hi <%= data.name %>!', null, { 'variable': 'data' });
compiled.source;
// => function(data) {
var __t, __p = '', __e = _.escape;
__p += 'hi ' + ((__t = ( data.name )) == null ? '' : __t) + '!';
return __p;
}
// using the `source` property to inline compiled templates for meaningful
// line numbers in error messages and a stack trace
fs.writeFileSync(path.join(cwd, 'jst.js'), '\
var JST = {\
"main": ' + _.template(mainText).source + '\
};\
');Executes the callback function n times, returning an array of the results of each callback execution. The callback is bound to thisArg and invoked with one argument; (index).
n(Number): The number of times to execute the callback.callback(Function): The function called per iteration.[thisArg](Mixed): Thethisbinding ofcallback.
(Array): Returns a new array of the results of each callback execution.
var diceRolls = _.times(3, _.partial(_.random, 1, 6));
// => [3, 6, 4]
_.times(3, function(n) { mage.castSpell(n); });
// => calls `mage.castSpell(n)` three times, passing `n` of `0`, `1`, and `2` respectively
_.times(3, function(n) { this.cast(n); }, mage);
// => also calls `mage.castSpell(n)` three timesThe inverse of _.escape, this method converts the HTML entities &, <, >, ", and ' in string to their corresponding characters.
string(String): The string to unescape.
(String): Returns the unescaped string.
_.unescape('Moe, Larry & Curly');
// => 'Moe, Larry & Curly'Generates a unique ID. If prefix is passed, the ID will be appended to it.
[prefix](String): The value to prefix the ID with.
(String): Returns the unique ID.
_.uniqueId('contact_');
// => 'contact_104'
_.uniqueId();
// => '105'A reference to the lodash function.
(String): The semantic version number.
(Object): An object used to flag environments features.
(Boolean): Detect if an arguments object's [[Class]] is resolvable (all but Firefox < 4, IE < 9).
(Boolean): Detect if arguments objects are Object objects (all but Narwhal and Opera < 10.5).
(Boolean): Detect if name or message properties of Error.prototype are enumerable by default. (IE < 9, Safari < 5.1)
(Boolean): Detect if prototype properties are enumerable by default.
Firefox < 3.6, Opera > 9.50 - Opera < 11.60, and Safari < 5.1 (if the prototype or a property on the prototype has been set) incorrectly sets a function's prototype property [[Enumerable]] value to true.
(Boolean): Detect if Function#bind exists and is inferred to be fast (all but V8).
(Boolean): Detect if arguments object indexes are non-enumerable (Firefox < 4, IE < 9, PhantomJS, Safari < 5.1).
(Boolean): Detect if properties shadowing those on Object.prototype are non-enumerable.
In IE < 9 an objects own properties, shadowing non-enumerable ones, are made non-enumerable as well (a.k.a the JScript [[DontEnum]] bug).
(Boolean): Detect if own properties are iterated after inherited properties (all but IE < 9).
(Boolean): Detect if Array#shift and Array#splice augment array-like objects correctly.
Firefox < 10, IE compatibility mode, and IE < 9 have buggy Array shift() and splice() functions that fail to remove the last element, value[0], of array-like objects even though the length property is set to 0. The shift() method is buggy in IE 8 compatibility mode, while splice() is buggy regardless of mode in IE < 9 and buggy in compatibility mode in IE 9.
(Boolean): Detect lack of support for accessing string characters by index.
IE < 8 can't access characters by index and IE 8 can only access characters by index on string literals.
(Object): By default, the template delimiters used by Lo-Dash are similar to those in embedded Ruby (ERB). Change the following template settings to use alternative delimiters.
(RegExp): Used to detect data property values to be HTML-escaped.
(RegExp): Used to detect code to be evaluated.
(RegExp): Used to detect data property values to inject.
(String): Used to reference the data object in the template text.
(Object): Used to import variables into the compiled template.