Shared Flashcard Set

Details

Lodash
Lodash terms
315
Computer Science
Professional
04/13/2021
Click here to study/print these flashcards.

Create your own flash cards! Sign up here.

Additional Computer Science Flashcards

 

 

Cards

Term
VERSION
 Definition
The semantic version number.
Term
_
 Definition

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

var wrapped = f([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
Term
add
 Definition
_.f(6, 4); // 10
Term
after
 Definition

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

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

_.forEach(saves, type => { asyncSave({ 'type': type, 'complete': done });

}); // => Logs 'done saving!' after the two async saves have completed.
Term
ary
 Definition
_.map(['6', '8', '10'], _.f(parseInt, 1)); // [6, 8, 10]
Term
assign
 Definition

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

function Bar() { this.c = 3; }

Foo.prototype.b = 2;

Bar.prototype.d = 4;

_.f({ 'a': 0 }, new Foo, new Bar); // { 'a': 1, 'c': 3 }
Term
assignIn
 Definition

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

function Bar() { this.c = 3; }

Foo.prototype.b = 2;

Bar.prototype.d = 4;

_.f({ 'a': 0 }, new Foo, new Bar); // { 'a': 1, 'b': 2, 'c': 3, 'd': 4 }
Term
assignInWith
 Definition

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

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

defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 }); // { 'a': 1, 'b': 2 }
Term
assignWith
 Definition

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

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

defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 }); // { 'a': 1, 'b': 2 }
Term
at
 Definition

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

_.f(object, ['a[0].b.c', 'a[1]']); // [3, 4]
Term
attempt
 Definition

// Avoid throwing errors for invalid selectors.

var elements = _.f(function(selector) { return document.querySelectorAll(selector); }, '>_>');

if (_.isError(elements)) { elements = []; }
Term
before
 Definition
jQuery(element).on('click', _.f(5, addContactToList)); // Allows adding up to 4 contacts to the list.
Term
bind
 Definition

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

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

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

var bound = _.f(greet, object, _, '!');

bound('hi'); // 'hi fred!'
Term
bindAll
 Definition

var view = { 'label': 'docs', 'click': () => { console.log('clicked ' + this.label); } };

_.f(view, ['click']);

jQuery(element).on('click', view.click); // Logs 'clicked docs' when clicked.
Term
bindKey
 Definition
var object = {
'user': 'fred',
'greet': function(greeting, punctuation) {
return greeting + ' ' + this.user + punctuation;
}
};

var bound = _.f(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 = _.f(object, 'greet', _, '!');
bound('hi');
// => 'hiya fred!'
Term
camelCase
 Definition
_.f('Foo Bar');
// => 'fooBar'

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

_.f('__FOO_BAR__');
// => 'fooBar'
Term
capitalize
 Definition
_.f('FRED');
// => 'Fred'
Term
castArray
 Definition
_.f(1);
// => [1]

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

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

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

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

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

var array = [1, 2, 3];
console.log(_.f(array) === array);
// => true
Term
ceil
 Definition
_.f(4.006);
// => 5

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

_.f(6040, -2);
// => 6100
Term
chain
 Definition
var users = [
{ 'user': 'barney', 'age': 36 },
{ 'user': 'fred', 'age': 40 },
{ 'user': 'pebbles', 'age': 1 }
];

var youngest = _
.f(users)
.sortBy('age')
.map(function(o) {
return o.user + ' is ' + o.age;
})
.head()
.value();
// => 'pebbles is 1'
Term
chunk
 Definition
_.f(['a', 'b', 'c', 'd'], 2);
// => [['a', 'b'], ['c', 'd']]

_.f(['a', 'b', 'c', 'd'], 3);
// => [['a', 'b', 'c'], ['d']]
Term
clamp
 Definition
_.f(-10, -5, 5);
// => -5

_.f(10, -5, 5);
// => 5
Term
clone
 Definition
var objects = [{ 'a': 1 }, { 'b': 2 }];

var shallow = _.f(objects);
console.log(shallow[0] === objects[0]);
// => true
Term
cloneDeep
 Definition
var objects = [{ 'a': 1 }, { 'b': 2 }];

var deep = _.f(objects);
console.log(deep[0] === objects[0]);
// => false
Term
cloneDeepWith
 Definition
function customizer(value) {
if (_.isElement(value)) {
return value.cloneNode(true);
}
}

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

console.log(el === document.body);
// => false
console.log(el.nodeName);
// => 'BODY'
console.log(el.childNodes.length);
// => 20
Term
cloneWith
 Definition
function customizer(value) {
if (_.isElement(value)) {
return value.cloneNode(false);
}
}

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

console.log(el === document.body);
// => false
console.log(el.nodeName);
// => 'BODY'
console.log(el.childNodes.length);
// => 0
Term
compact
 Definition
_.f([0, 1, false, 2, '', 3]);
// => [1, 2, 3]
Term
concat
 Definition
var array = [1];
var other = _.f(array, 2, [3], [[4]]);

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

console.log(array);
// => [1]
Term
cond
 Definition
var func = _.f([
[_.matches({ 'a': 1 }), _.constant('matches A')],
[_.conforms({ 'b': _.isNumber }), _.constant('matches B')],
[_.stubTrue, _.constant('no match')]
]);

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

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

func({ 'a': '1', 'b': '2' });
// => 'no match'
Term
conforms
 Definition
var objects = [
{ 'a': 2, 'b': 1 },
{ 'a': 1, 'b': 2 }
];

_.filter(objects, _.f({ 'b': function(n) { return n > 1; } }));
// => [{ 'a': 1, 'b': 2 }]
Term
conformsTo
 Definition
var object = { 'a': 1, 'b': 2 };

_.f(object, { 'b': function(n) { return n > 1; } });
// => true

_.f(object, { 'b': function(n) { return n > 2; } });
// => false
Term
constant
 Definition
var objects = _.times(2, _.f({ 'a': 1 }));

console.log(objects);
// => [{ 'a': 1 }, { 'a': 1 }]

console.log(objects[0] === objects[1]);
// => true
Term
countBy
 Definition
_.f([6.1, 4.2, 6.3], Math.floor);
// => { '4': 1, '6': 2 }

// The `_.property` iteratee shorthand.
_.f(['one', 'two', 'three'], 'length');
// => { '3': 2, '5': 1 }
Term
create
 Definition
function Shape() {
this.x = 0;
this.y = 0;
}

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

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

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

circle instanceof Shape;
// => true
Term
curry
 Definition
var abc = function(a, b, c) {
return [a, b, c];
};

var curried = _.f(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]
Term
curryRight
 Definition
var abc = function(a, b, c) {
return [a, b, c];
};

var curried = _.f(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]
Term
debounce
 Definition
// Avoid costly calculations while the window size is in flux.
jQuery(window).on('resize', _.f(calculateLayout, 150));

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

// Ensure `batchLog` is invoked once after 1 second of debounced calls.
var debounced = _.f(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);
Term
deburr
 Definition
_.f('déjà vu');
// => 'deja vu'
Term
defaultTo
 Definition
_.f(1, 10);
// => 1

_.f(undefined, 10);
// => 10
Term
defaults
 Definition
_.f({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
// => { 'a': 1, 'b': 2 }
Term
defaultsDeep
 Definition
_.f({ 'a': { 'b': 2 } }, { 'a': { 'b': 1, 'c': 3 } });
// => { 'a': { 'b': 2, 'c': 3 } }
Term
defer
 Definition
_.f(function(text) {
console.log(text);
}, 'deferred');
// => Logs 'deferred' after one millisecond.
Term
delay
 Definition
_.f(function(text) {
console.log(text);
}, 1000, 'later');
// => Logs 'later' after one second.
Term
difference
 Definition
_.f([2, 1], [2, 3]);
// => [1]
Term
differenceBy
 Definition
_.f([2.1, 1.2], [2.3, 3.4], Math.floor);
// => [1.2]

// The `_.property` iteratee shorthand.
_.f([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], 'x');
// => [{ 'x': 2 }]
Term
differenceWith
 Definition
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];

_.f(objects, [{ 'x': 1, 'y': 2 }], _.isEqual);
// => [{ 'x': 2, 'y': 1 }]
Term
divide
 Definition
_.f(6, 4);
// => 1.5
Term
drop
 Definition
_.f([1, 2, 3]);
// => [2, 3]

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

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

_.f([1, 2, 3], 0);
// => [1, 2, 3]
Term
dropRight
 Definition
_.f([1, 2, 3]);
// => [1, 2]

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

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

_.f([1, 2, 3], 0);
// => [1, 2, 3]
Term
dropRightWhile
 Definition
var users = [
{ 'user': 'barney', 'active': true },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': false }
];

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

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

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

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

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => objects for ['barney', 'fred', 'pebbles']
Term
endsWith
 Definition
_.f('abc', 'c');
// => true

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

_.f('abc', 'b', 2);
// => true
Term
eq
 Definition
var object = { 'a': 1 };
var other = { 'a': 1 };

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

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

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

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

_.f(NaN, NaN);
// => true
Term
escape
 Definition
_.f('fred, barney, & pebbles');
// => 'fred, barney, & pebbles'
Term
escapeRegExp
 Definition
_.f('[lodash](https://lodash.com/)');
// => '\[lodash\]\(https://lodash\.com/\)'
Term
every
 Definition
_.f([true, 1, null, 'yes'], Boolean);
// => false

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => false
Term
fill
 Definition
var array = [1, 2, 3];

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

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

_.f([4, 6, 8, 10], '*', 1, 3);
// => [4, '*', '*', 10]
Term
filter
 Definition
var users = [
{ 'user': 'barney', 'age': 36, 'active': true },
{ 'user': 'fred', 'age': 40, 'active': false }
];

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => objects for ['barney']
Term
find
 Definition
var users = [
{ 'user': 'barney', 'age': 36, 'active': true },
{ 'user': 'fred', 'age': 40, 'active': false },
{ 'user': 'pebbles', 'age': 1, 'active': true }
];

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => object for 'barney'
Term
findIndex
 Definition
var users = [
{ 'user': 'barney', 'active': false },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': true }
];

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => 2
Term
findKey
 Definition
var users = {
'barney': { 'age': 36, 'active': true },
'fred': { 'age': 40, 'active': false },
'pebbles': { 'age': 1, 'active': true }
};

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => 'barney'
Term
findLast
 Definition
_.f([1, 2, 3, 4], function(n) {
return n % 2 == 1;
});
// => 3
Term
findLastIndex
 Definition
var users = [
{ 'user': 'barney', 'active': true },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': false }
];

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => 0
Term
findLastKey
 Definition
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 `_.f` returns 'barney'

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => 'pebbles'
Term
flatMap
 Definition
function duplicate(n) {
return [n, n];
}

_.f([1, 2], duplicate);
// => [1, 1, 2, 2]
Term
flatMapDeep
 Definition
function duplicate(n) {
return [[[n, n]]];
}

_.f([1, 2], duplicate);
// => [1, 1, 2, 2]
Term
flatMapDepth
 Definition
function duplicate(n) {
return [[[n, n]]];
}

_.f([1, 2], duplicate, 2);
// => [[1, 1], [2, 2]
Term
flatten
 Definition
_.f([1, [2, [3, [4]], 5]]);
// => [1, 2, [3, [4]], 5]
Term
flattenDeep
 Definition
_.f([1, [2, [3, [4]], 5]]);
// => [1, 2, 3, 4, 5]
Term
flattenDepth
 Definition
var array = [1, [2, [3, [4]], 5]];

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

_.f(array, 2);
// => [1, 2, 3, [4], 5]
Term
flip
 Definition
var flipped = _.f(function() {
return _.toArray(arguments);
});

flipped('a', 'b', 'c', 'd');
// => ['d', 'c', 'b', 'a']
Term
floor
 Definition
_.f(4.006);
// => 4

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

_.f(4060, -2);
// => 4000
Term
flow
 Definition
function square(n) {
return n * n;
}

var addSquare = _.f([_.add, square]);
addSquare(1, 2);
// => 9
Term
flowRight
 Definition
function square(n) {
return n * n;
}

var addSquare = _.f([square, _.add]);
addSquare(1, 2);
// => 9
Term
forEach
 Definition
_.f([1, 2], function(value) {
console.log(value);
});
// => Logs `1` then `2`.

_.f({ 'a': 1, 'b': 2 }, function(value, key) {
console.log(key);
});
// => Logs 'a' then 'b' (iteration order is not guaranteed).
Term
forEachRight
 Definition
_.f([1, 2], function(value) {
console.log(value);
});
// => Logs `2` then `1`.
Term
forIn
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo, function(value, key) {
console.log(key);
});
// => Logs 'a', 'b', then 'c' (iteration order is not guaranteed).
Term
forInRight
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo, function(value, key) {
console.log(key);
});
// => Logs 'c', 'b', then 'a' assuming `_.forIn` logs 'a', 'b', then 'c'.
Term
forOwn
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo, function(value, key) {
console.log(key);
});
// => Logs 'a' then 'b' (iteration order is not guaranteed).
Term
forOwnRight
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo, function(value, key) {
console.log(key);
});
// => Logs 'b' then 'a' assuming `_.forOwn` logs 'a' then 'b'.
Term
fromPairs
 Definition
_.f([['a', 1], ['b', 2]]);
// => { 'a': 1, 'b': 2 }
Term
functions
 Definition
function Foo() {
this.a = _.constant('a');
this.b = _.constant('b');
}

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

_.f(new Foo);
// => ['a', 'b']
Term
functionsIn
 Definition
function Foo() {
this.a = _.constant('a');
this.b = _.constant('b');
}

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

_.f(new Foo);
// => ['a', 'b', 'c']
Term
get
 Definition
var object = { 'a': [{ 'b': { 'c': 3 } }] };

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

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

_.f(object, 'a.b.c', 'default');
// => 'default'
Term
groupBy
 Definition
_.f([6.1, 4.2, 6.3], Math.floor);
// => { '4': [4.2], '6': [6.1, 6.3] }

// The `_.property` iteratee shorthand.
_.f(['one', 'two', 'three'], 'length');
// => { '3': ['one', 'two'], '5': ['three'] }
Term
gt
 Definition
_.f(3, 1);
// => true

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

_.f(1, 3);
// => false
Term
gte
 Definition
_.f(3, 1);
// => true

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

_.f(1, 3);
// => false
Term
has
 Definition
var object = { 'a': { 'b': 2 } };
var other = _.create({ 'a': _.create({ 'b': 2 }) });

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

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

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

_.f(other, 'a');
// => false
Term
hasIn
 Definition
var object = _.create({ 'a': _.create({ 'b': 2 }) });

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

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

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

_.f(object, 'b');
// => false
Term
head
 Definition
_.f([1, 2, 3]);
// => 1

_.head([]);
// => undefined
Term
identity
 Definition
var object = { 'a': 1 };

console.log(_.f(object) === object);
// => true
Term
inRange
 Definition
_.f(3, 2, 4);
// => true

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

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

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

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

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

_.f(-3, -2, -6);
// => true
Term
includes
 Definition
_.f([1, 2, 3], 1);
// => true

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

_.f({ 'a': 1, 'b': 2 }, 1);
// => true

_.f('abcd', 'bc');
// => true
Term
indexOf
 Definition
_.f([1, 2, 1, 2], 2);
// => 1

// Search from the `fromIndex`.
_.f([1, 2, 1, 2], 2, 2);
// => 3
Term
initial
 Definition
_.f([1, 2, 3]);
// => [1, 2]
Term
intersection
 Definition
_.f([2, 1], [2, 3]);
// => [2]
Term
intersectionBy
 Definition
_.f([2.1, 1.2], [2.3, 3.4], Math.floor);
// => [2.1]

// The `_.property` iteratee shorthand.
_.f([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 1 }]
Term
intersectionWith
 Definition
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.f(objects, others, _.isEqual);
// => [{ 'x': 1, 'y': 2 }]
Term
invert
 Definition
var object = { 'a': 1, 'b': 2, 'c': 1 };

_.f(object);
// => { '1': 'c', '2': 'b' }
Term
invertBy
 Definition
var object = { 'a': 1, 'b': 2, 'c': 1 };

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

_.f(object, function(value) {
return 'group' + value;
});
// => { 'group1': ['a', 'c'], 'group2': ['b'] }
Term
invoke
 Definition
var object = { 'a': [{ 'b': { 'c': [1, 2, 3, 4] } }] };

_.f(object, 'a[0].b.c.slice', 1, 3);
// => [2, 3]
Term
invokeMap
 Definition
_.f([[5, 1, 7], [3, 2, 1]], 'sort');
// => [[1, 5, 7], [1, 2, 3]]

_.f([123, 456], String.prototype.split, '');
// => [['1', '2', '3'], ['4', '5', '6']]
Term
isArguments
 Definition
_.f(function() { return arguments; }());
// => true

_.f([1, 2, 3]);
// => false
Term
isArray
 Definition
_.f([1, 2, 3]);
// => true

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

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

_.f(_.noop);
// => false
Term
isArrayBuffer
 Definition
_.f(new ArrayBuffer(2));
// => true

_.f(new Array(2));
// => false
Term
isArrayLike
 Definition
_.f([1, 2, 3]);
// => true

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

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

_.f(_.noop);
// => false
Term
isArrayLikeObject
 Definition
_.f([1, 2, 3]);
// => true

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

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

_.f(_.noop);
// => false
Term
isBoolean
 Definition
_.f(false);
// => true

_.f(null);
// => false
Term
isBuffer
 Definition
_.f(new Buffer(2));
// => true

_.f(new Uint8Array(2));
// => false
Term
isDate
 Definition
_.f(new Date); // => true _.f('Mon April 23 2012'); // => false
Term
isElement
 Definition

_.f(document.body);

// => true

 

_.f("<body>");

// => false
Term
isEmpty
 Definition
_.f(null);
// => true

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

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

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

_.f({ 'a': 1 });
// => false
Term
isEqual
 Definition
var object = { 'a': 1 };
var other = { 'a': 1 };

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

object === other;
// => false
Term
isEqualWith
 Definition
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'];

_.f(array, other, customizer);
// => true
Term
isError
 Definition
_.f(new Error);
// => true

_.f(Error);
// => false
Term
isFinite
 Definition
_.f(3);
// => true

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

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

_.f('3');
// => false
Term
isFunction
 Definition
_.f(_);
// => true

_.f(/abc/);
// => false
Term
isInteger
 Definition
_.f(3);
// => true

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

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

_.f('3');
// => false
Term
isLength
 Definition
_.f(3);
// => true

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

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

_.f('3');
// => false
Term
isMap
 Definition
_.f(new Map);
// => true

_.f(new WeakMap);
// => false
Term
isMatch
 Definition
var object = { 'a': 1, 'b': 2 };

_.f(object, { 'b': 2 });
// => true

_.f(object, { 'b': 1 });
// => false
Term
isMatchWith
 Definition
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' };

_.f(object, source, customizer);
// => true
Term
isNaN
 Definition
_.f(NaN);
// => true

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

isNaN(undefined);
// => true

_.f(undefined);
// => false
Term
isNative
 Definition
_.f(Array.prototype.push);
// => true

_.f(_);
// => false
Term
isNil
 Definition
_.f(null);
// => true

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

_.f(NaN);
// => false
Term
isNull
 Definition
_.f(null);
// => true

_.f(void 0);
// => false
Term
isNumber
 Definition
_.f(3);
// => true

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

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

_.f('3');
// => false
Term
isObject
 Definition
_.f({});
// => true

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

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

_.f(null);
// => false
Term
isObjectLike
 Definition
_.f({});
// => true

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

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

_.f(null);
// => false
Term
isPlainObject
 Definition
function Foo() {
this.a = 1;
}

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

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

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

_.f(Object.create(null));
// => true
Term
isRegExp
 Definition
_.f(/abc/);
// => true

_.f('/abc/');
// => false
Term
isSafeInteger
 Definition
_.f(3);
// => true

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

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

_.f('3');
// => false
Term
isSet
 Definition
_.f(new Set);
// => true

_.f(new WeakSet);
// => false
Term
isString
 Definition
_.f('abc');
// => true

_.f(1);
// => false
Term
isSymbol
 Definition
_.f(Symbol.iterator);
// => true

_.f('abc');
// => false
Term
isTypedArray
 Definition
_.f(new Uint8Array);
// => true

_.f([]);
// => false
Term
isUndefined
 Definition
_.f(void 0);
// => true

_.f(null);
// => false
Term
isWeakMap
 Definition
_.f(new WeakMap);
// => true

_.f(new Map);
// => false
Term
isWeakSet
 Definition
_.f(new WeakSet);
// => true

_.f(new Set);
// => false
Term
iteratee
 Definition
var users = [
{ 'user': 'barney', 'age': 36, 'active': true },
{ 'user': 'fred', 'age': 40, 'active': false }
];

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

// The `_.matchesProperty` iteratee shorthand.
_.filter(users, _.f(['user', 'fred']));
// => [{ 'user': 'fred', 'age': 40 }]

// The `_.property` iteratee shorthand.
_.map(users, _.f('user'));
// => ['barney', 'fred']

// Create custom iteratee shorthands.
_.f = _.wrap(_.iteratee, function(iteratee, func) {
return !_.isRegExp(func) ? iteratee(func) : function(string) {
return func.test(string);
};
});

_.filter(['abc', 'def'], /ef/);
// => ['def']
Term
join
 Definition
_.f(['a', 'b', 'c'], '~');
// => 'a~b~c'
Term
kebabCase
 Definition
_.f('Foo Bar');
// => 'foo-bar'

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

_.f('__FOO_BAR__');
// => 'foo-bar'
Term
keyBy
 Definition
var array = [
{ 'dir': 'left', 'code': 97 },
{ 'dir': 'right', 'code': 100 }
];

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

_.f(array, 'dir');
// => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
Term
keys
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

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

_.f('hi');
// => ['0', '1']
Term
keysIn
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo);
// => ['a', 'b', 'c'] (iteration order is not guaranteed)
Term
last
 Definition
_.f([1, 2, 3]);
// => 3
Term
lastIndexOf
 Definition
_.f([1, 2, 1, 2], 2);
// => 3

// Search from the `fromIndex`.
_.f([1, 2, 1, 2], 2, 2);
// => 1
Term
lowerCase
 Definition
_.f('--Foo-Bar--');
// => 'foo bar'

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

_.f('__FOO_BAR__');
// => 'foo bar'
Term
lowerFirst
 Definition
_.f('Fred');
// => 'fred'

_.f('FRED');
// => 'fRED'
Term
lt
 Definition
_.f(1, 3);
// => true

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

_.f(3, 1);
// => false
Term
lte
 Definition
_.f(1, 3);
// => true

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

_.f(3, 1);
// => false
Term
map
 Definition
function square(n) {
return n * n;
}

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

_.f({ 'a': 4, 'b': 8 }, square);
// => [16, 64] (iteration order is not guaranteed)

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

// The `_.property` iteratee shorthand.
_.f(users, 'user');
// => ['barney', 'fred']
Term
mapKeys
 Definition
_.f({ 'a': 1, 'b': 2 }, function(value, key) {
return key + value;
});
// => { 'a1': 1, 'b2': 2 }
Term
mapValues
 Definition
var users = {
'fred': { 'user': 'fred', 'age': 40 },
'pebbles': { 'user': 'pebbles', 'age': 1 }
};

_.f(users, function(o) { return o.age; });
// => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)

// The `_.property` iteratee shorthand.
_.f(users, 'age');
// => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
Term
matches
 Definition
var objects = [
{ 'a': 1, 'b': 2, 'c': 3 },
{ 'a': 4, 'b': 5, 'c': 6 }
];

_.filter(objects, _.f({ 'a': 4, 'c': 6 }));
// => [{ 'a': 4, 'b': 5, 'c': 6 }]
Term
matchesProperty
 Definition
var objects = [
{ 'a': 1, 'b': 2, 'c': 3 },
{ 'a': 4, 'b': 5, 'c': 6 }
];

_.find(objects, _.f('a', 4));
// => { 'a': 4, 'b': 5, 'c': 6 }
Term
max
 Definition
_.f([4, 2, 8, 6]);
// => 8

_.f([]);
// => undefined
Term
maxBy
 Definition
var objects = [{ 'n': 1 }, { 'n': 2 }];

_.f(objects, function(o) { return o.n; });
// => { 'n': 2 }

// The `_.property` iteratee shorthand.
_.f(objects, 'n');
// => { 'n': 2 }
Term
mean
 Definition
_.f([4, 2, 8, 6]);
// => 5
Term
meanBy
 Definition
var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];

_.f(objects, function(o) { return o.n; });
// => 5

// The `_.property` iteratee shorthand.
_.f(objects, 'n');
// => 5
Term
memoize
 Definition
var object = { 'a': 1, 'b': 2 };
var other = { 'c': 3, 'd': 4 };

var values = _.f(_.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;
Term
merge
 Definition
var object = {
'a': [{ 'b': 2 }, { 'd': 4 }]
};

var other = {
'a': [{ 'c': 3 }, { 'e': 5 }]
};

_.f(object, other);
// => { 'a': [{ 'b': 2, 'c': 3 }, { 'd': 4, 'e': 5 }] }
Term
mergeWith
 Definition
function customizer(objValue, srcValue) {
if (_.isArray(objValue)) {
return objValue.concat(srcValue);
}
}

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

_.f(object, other, customizer);
// => { 'a': [1, 3], 'b': [2, 4] }
Term
method
 Definition
var objects = [
{ 'a': { 'b': _.constant(2) } },
{ 'a': { 'b': _.constant(1) } }
];

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

_.map(objects, _.f(['a', 'b']));
// => [2, 1]
Term
methodOf
 Definition
var array = _.times(3, _.constant),
object = { 'a': array, 'b': array, 'c': array };

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

_.map([['a', '2'], ['c', '0']], _.f(object));
// => [2, 0]
Term
min
 Definition
_.f([4, 2, 8, 6]);
// => 2

_.f([]);
// => undefined
Term
minBy
 Definition
var objects = [{ 'n': 1 }, { 'n': 2 }];

_.f(objects, function(o) { return o.n; });
// => { 'n': 1 }

// The `_.property` iteratee shorthand.
_.f(objects, 'n');
// => { 'n': 1 }
Term
mixin
 Definition
function vowels(string) {
return _.filter(string, function(v) {
return /[aeiou]/i.test(v);
});
}

_.f({ 'vowels': vowels });
_.vowels('fred');
// => ['e']

_('fred').vowels().value();
// => ['e']

_.f({ 'vowels': vowels }, { 'chain': false });
_('fred').vowels();
// => ['e']
Term
multiply
 Definition
_.f(6, 4);
// => 24
Term
negate
 Definition
function isEven(n) {
return n % 2 == 0;
}

_.filter([1, 2, 3, 4, 5, 6], _.f(isEven));
// => [1, 3, 5]
Term
noConflict
 Definition
var lodash = _.f();
Term
noop
 Definition
_.times(2, _.f);
// => [undefined, undefined]
Term
now
 Definition
_.defer(function(stamp) {
console.log(_.now() - stamp);
}, _.f());
// => Logs the number of milliseconds it took for the deferred invocation.
Term
nth
 Definition
var array = ['a', 'b', 'c', 'd'];

_.f(array, 1);
// => 'b'

_.f(array, -2);
// => 'c';
Term
nthArg
 Definition
var func = _.f(1);
func('a', 'b', 'c', 'd');
// => 'b'

var func = _.f(-2);
func('a', 'b', 'c', 'd');
// => 'c'
Term
omit
 Definition
var object = { 'a': 1, 'b': '2', 'c': 3 };

_.f(object, ['a', 'c']);
// => { 'b': '2' }
Term
omitBy
 Definition
var object = { 'a': 1, 'b': '2', 'c': 3 };

_.f(object, _.isNumber);
// => { 'b': '2' }
Term
once
 Definition
var initialize = _.f(createApplication);
initialize();
initialize();
// => `createApplication` is invoked once
Term
orderBy
 Definition
var users = [
{ 'user': 'fred', 'age': 48 },
{ 'user': 'barney', 'age': 34 },
{ 'user': 'fred', 'age': 40 },
{ 'user': 'barney', 'age': 36 }
];

// Sort by `user` in ascending order and by `age` in descending order.
_.f(users, ['user', 'age'], ['asc', 'desc']);
// => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]
Term
over
 Definition
var func = _.f([Math.max, Math.min]);

func(1, 2, 3, 4);
// => [4, 1]
Term
overArgs
 Definition
function doubled(n) {
return n * 2;
}

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

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

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

func(10, 5);
// => [100, 10]
Term
overEvery
 Definition
var func = _.f([Boolean, isFinite]);

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

func(null);
// => false

func(NaN);
// => false
Term
overSome
 Definition
var func = _.f([Boolean, isFinite]);

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

func(null);
// => true

func(NaN);
// => false
Term
pad
 Definition
_.f('abc', 8);
// => ' abc '

_.f('abc', 8, '_-');
// => '_-abc_-_'

_.f('abc', 3);
// => 'abc'
Term
padEnd
 Definition
_.f('abc', 6);
// => 'abc '

_.f('abc', 6, '_-');
// => 'abc_-_'

_.f('abc', 3);
// => 'abc'
Term
padStart
 Definition
_.f('abc', 6);
// => ' abc'

_.f('abc', 6, '_-');
// => '_-_abc'

_.f('abc', 3);
// => 'abc'
Term
parseInt
 Definition
_.f('08');
// => 8

_.map(['6', '08', '10'], _.f);
// => [6, 8, 10]
Term
partial
 Definition
function greet(greeting, name) {
return greeting + ' ' + name;
}

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

// Partially applied with placeholders.
var greetFred = _.f(greet, _, 'fred');
greetFred('hi');
// => 'hi fred'
Term
partialRight
 Definition
function greet(greeting, name) {
return greeting + ' ' + name;
}

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

// Partially applied with placeholders.
var sayHelloTo = _.f(greet, 'hello', _);
sayHelloTo('fred');
// => 'hello fred'
Term
partition
 Definition
var users = [
{ 'user': 'barney', 'age': 36, 'active': false },
{ 'user': 'fred', 'age': 40, 'active': true },
{ 'user': 'pebbles', 'age': 1, 'active': false }
];

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => objects for [['fred'], ['barney', 'pebbles']]
Term
pick
 Definition
var object = { 'a': 1, 'b': '2', 'c': 3 };

_.f(object, ['a', 'c']);
// => { 'a': 1, 'c': 3 }
Term
pickBy
 Definition
var object = { 'a': 1, 'b': '2', 'c': 3 };

_.f(object, _.isNumber);
// => { 'a': 1, 'c': 3 }
Term
property
 Definition
var objects = [
{ 'a': { 'b': 2 } },
{ 'a': { 'b': 1 } }
];

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

_.map(_.sortBy(objects, _.f(['a', 'b'])), 'a.b');
// => [1, 2]
Term
propertyOf
 Definition
var array = [0, 1, 2],
object = { 'a': array, 'b': array, 'c': array };

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

_.map([['a', '2'], ['c', '0']], _.f(object));
// => [2, 0]
Term
prototype
 Definition
var wrapped = f([1, 2]);

wrapped[Symbol.iterator]() === wrapped;
// => true

Array.from(wrapped);
// => [1, 2]
Term
prototype.at
 Definition
var object = { 'a': [{ 'b': { 'c': 3 } }, 4] };

f(object).f(['a[0].b.c', 'a[1]']).value();
// => [3, 4]
Term
prototype.chain
 Definition
var users = [
{ 'user': 'barney', 'age': 36 },
{ 'user': 'fred', 'age': 40 }
];

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

// A sequence with explicit chaining.
f(users)
.f()
.head()
.pick('user')
.value();
// => { 'user': 'barney' }
Term
prototype.commit
 Definition
var array = [1, 2];
var wrapped = f(array).push(3);

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

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

wrapped.last();
// => 3

console.log(array);
// => [1, 2, 3]
Term
prototype.next
 Definition
var wrapped = f([1, 2]);

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

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

wrapped.f();
// => { 'done': true, 'value': undefined }
Term
prototype.plant
 Definition
function square(n) {
return n * n;
}

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

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

wrapped.value();
// => [1, 4]
Term
prototype.reverse
 Definition
var array = [1, 2, 3];

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

console.log(array);
// => [3, 2, 1]
Term
prototype.value
 Definition
f([1, 2, 3]).f();
// => [1, 2, 3]
Term
pull
 Definition
var array = ['a', 'b', 'c', 'a', 'b', 'c'];

_.f(array, 'a', 'c');
console.log(array);
// => ['b', 'b']
Term
pullAll
 Definition
var array = ['a', 'b', 'c', 'a', 'b', 'c'];

_.f(array, ['a', 'c']);
console.log(array);
// => ['b', 'b']
Term
pullAllBy
 Definition
var array = [{ 'x': 1 }, { 'x': 2 }, { 'x': 3 }, { 'x': 1 }];

_.f(array, [{ 'x': 1 }, { 'x': 3 }], 'x');
console.log(array);
// => [{ 'x': 2 }]
Term
pullAllWith
 Definition
var array = [{ 'x': 1, 'y': 2 }, { 'x': 3, 'y': 4 }, { 'x': 5, 'y': 6 }];

_.f(array, [{ 'x': 3, 'y': 4 }], _.isEqual);
console.log(array);
// => [{ 'x': 1, 'y': 2 }, { 'x': 5, 'y': 6 }]
Term
pullAt
 Definition
var array = ['a', 'b', 'c', 'd'];
var pulled = _.f(array, [1, 3]);

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

console.log(pulled);
// => ['b', 'd']
Term
random
 Definition
_.f(0, 5);
// => an integer between 0 and 5

_.f(5);
// => also an integer between 0 and 5

_.f(5, true);
// => a floating-point number between 0 and 5

_.f(1.2, 5.2);
// => a floating-point number between 1.2 and 5.2
Term
range
 Definition
_.f(4);
// => [0, 1, 2, 3]

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

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

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

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

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

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

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

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

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

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

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

_.f(0);
// => []
Term
rearg
 Definition
var rearged = _.f(function(a, b, c) {
return [a, b, c];
}, [2, 0, 1]);

rearged('b', 'c', 'a')
// => ['a', 'b', 'c']
Term
reduce
 Definition
_.f([1, 2], function(sum, n) {
return sum + n;
}, 0);
// => 3

_.f({ '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)
Term
reduceRight
 Definition
var array = [[0, 1], [2, 3], [4, 5]];

_.f(array, function(flattened, other) {
return flattened.concat(other);
}, []);
// => [4, 5, 2, 3, 0, 1]
Term
reject
 Definition
var users = [
{ 'user': 'barney', 'age': 36, 'active': false },
{ 'user': 'fred', 'age': 40, 'active': true }
];

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

// The `_.matches` iteratee shorthand.
_.f(users, { 'age': 40, 'active': true });
// => objects for ['barney']

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => objects for ['barney']
Term
remove
 Definition
var array = [1, 2, 3, 4];
var evens = _.f(array, function(n) {
return n % 2 == 0;
});

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

console.log(evens);
// => [2, 4]
Term
repeat
 Definition
_.f('*', 3);
// => '***'

_.f('abc', 2);
// => 'abcabc'

_.f('abc', 0);
// => ''
Term
replace
 Definition
_.f('Hi Fred', 'Fred', 'Barney');
// => 'Hi Barney'
Term
rest
 Definition
var say = _.f(function(what, names) {
return what + ' ' + _.initial(names).join(', ') +
(_.size(names) > 1 ? ', & ' : '') + _.last(names);
});

say('hello', 'fred', 'barney', 'pebbles');
// => 'hello fred, barney, & pebbles'
Term
result
 Definition
var object = { 'a': [{ 'b': { 'c1': 3, 'c2': _.constant(4) } }] };

_.f(object, 'a[0].b.c1');
// => 3

_.f(object, 'a[0].b.c2');
// => 4

_.f(object, 'a[0].b.c3', 'default');
// => 'default'

_.f(object, 'a[0].b.c3', _.constant('default'));
// => 'default'
Term
reverse
 Definition
var array = [1, 2, 3];

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

console.log(array);
// => [3, 2, 1]
Term
round
 Definition
_.f(4.006);
// => 4

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

_.f(4060, -2);
// => 4100
Term
runInContext
 Definition
_.mixin({ 'foo': _.constant('foo') });

var lodash = _.f();
lodash.mixin({ 'bar': lodash.constant('bar') });

_.isFunction(_.foo);
// => true
_.isFunction(_.bar);
// => false

lodash.isFunction(lodash.foo);
// => false
lodash.isFunction(lodash.bar);
// => true

// Create a suped-up `defer` in Node.js.
var defer = _.f({ 'setTimeout': setImmediate }).defer;
Term
sample
 Definition
_.f([1, 2, 3, 4]);
// => 2
Term
sampleSize
 Definition
_.f([1, 2, 3], 2);
// => [3, 1]

_.f([1, 2, 3], 4);
// => [2, 3, 1]
Term
set
 Definition
var object = { 'a': [{ 'b': { 'c': 3 } }] };

_.f(object, 'a[0].b.c', 4);
console.log(object.a[0].b.c);
// => 4

_.f(object, ['x', '0', 'y', 'z'], 5);
console.log(object.x[0].y.z);
// => 5
Term
setWith
 Definition
var object = {};

_.f(object, '[0][1]', 'a', Object);
// => { '0': { '1': 'a' } }
Term
shuffle
 Definition
_.f([1, 2, 3, 4]);
// => [4, 1, 3, 2]
Term
size
 Definition
_.f([1, 2, 3]);
// => 3

_.size({ 'a': 1, 'b': 2 });
// => 2

_.f('pebbles');
// => 7
Term
slice
 Definition
var array = [1, 2, 3];

_.f(array, 1, 2);
// => [2]
Term
snakeCase
 Definition
_.f('Foo Bar');
// => 'foo_bar'

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

_.f('--FOO-BAR--');
// => 'foo_bar'
Term
some
 Definition
_.f([null, 0, 'yes', false], Boolean);
// => true

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => true
Term
sortBy
 Definition
var users = [
{ 'user': 'fred', 'age': 48 },
{ 'user': 'barney', 'age': 36 },
{ 'user': 'fred', 'age': 40 },
{ 'user': 'barney', 'age': 34 }
];

_.f(users, [function(o) { return o.user; }]);
// => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]

_.f(users, ['user', 'age']);
// => objects for [['barney', 34], ['barney', 36], ['fred', 40], ['fred', 48]]
Term
sortedIndex
 Definition
_.f([30, 50], 40);
// => 1
Term
sortedIndexBy
 Definition
var objects = [{ 'x': 4 }, { 'x': 5 }];

_.f(objects, { 'x': 4 }, function(o) { return o.x; });
// => 0

// The `_.property` iteratee shorthand.
_.f(objects, { 'x': 4 }, 'x');
// => 0
Term
sortedIndexOf
 Definition
_.f([4, 5, 5, 5, 6], 5);
// => 1
Term
sortedLastIndex
 Definition
_.f([4, 5, 5, 5, 6], 5);
// => 4
Term
sortedLastIndexBy
 Definition
var objects = [{ 'x': 4 }, { 'x': 5 }];

_.f(objects, { 'x': 4 }, function(o) { return o.x; });
// => 1

// The `_.property` iteratee shorthand.
_.f(objects, { 'x': 4 }, 'x');
// => 1
Term
sortedLastIndexOf
 Definition
_.f([4, 5, 5, 5, 6], 5);
// => 3
Term
sortedUniq
 Definition
_.f([1, 1, 2]);
// => [1, 2]
Term
sortedUniqBy
 Definition
_.f([1.1, 1.2, 2.3, 2.4], Math.floor);
// => [1.1, 2.3]
Term
split
 Definition
_.f('a-b-c', '-', 2);
// => ['a', 'b']
Term
spread
 Definition
var say = _.f(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(_.f(function(x, y) {
return x + y;
}));
// => a Promise of 76
Term
startCase
 Definition
_.f('--foo-bar--');
// => 'Foo Bar'

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

_.f('__FOO_BAR__');
// => 'FOO BAR'
Term
startsWith
 Definition
_.f('abc', 'a');
// => true

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

_.f('abc', 'b', 1);
// => true
Term
stubArray
 Definition
var arrays = _.times(2, _.f);

console.log(arrays);
// => [[], []]

console.log(arrays[0] === arrays[1]);
// => false
Term
stubFalse
 Definition
_.times(2, _.f);
// => [false, false]
Term
stubObject
 Definition
var objects = _.times(2, _.f);

console.log(objects);
// => [{}, {}]

console.log(objects[0] === objects[1]);
// => false
Term
stubString
 Definition
_.times(2, _.f);
// => ['', '']
Term
stubTrue
 Definition
_.times(2, _.f);
// => [true, true]
Term
subtract
 Definition
_.f(6, 4);
// => 2
Term
sum
 Definition
_.f([4, 2, 8, 6]);
// => 20
Term
sumBy
 Definition
var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];

_.f(objects, function(o) { return o.n; });
// => 20

// The `_.property` iteratee shorthand.
_.f(objects, 'n');
// => 20
Term
tail
 Definition
_.f([1, 2, 3]);
// => [2, 3]
Term
take
 Definition
_.f([1, 2, 3]);
// => [1]

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

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

_.f([1, 2, 3], 0);
// => []
Term
takeRight
 Definition
_.f([1, 2, 3]);
// => [3]

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

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

_.f([1, 2, 3], 0);
// => []
Term
takeRightWhile
 Definition
var users = [
{ 'user': 'barney', 'active': true },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': false }
];

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => []
Term
takeWhile
 Definition
var users = [
{ 'user': 'barney', 'active': false },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': true }
];

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

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

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

// The `_.property` iteratee shorthand.
_.f(users, 'active');
// => []
Term
tap
 Definition
_([1, 2, 3])
.f(function(array) {
// Mutate input array.
array.pop();
})
.reverse()
.value();
// => [2, 1]
Term
template
 Definition

// Use the "interpolate" delimiter to create a compiled template.

var compiled = _.f('hello <%= user %>!');

compiled({ 'user': 'fred' });

// => 'hello fred!'

 

// Use the HTML "escape" delimiter to escape data property values.

var compiled = _.f('<b><%- value %></b>');

compiled({ 'value': '<script>' });

// => '<b>&lt;script&gt;</b>'

 

// Use the "evaluate" delimiter to execute JavaScript and generate HTML.

var compiled = _.f('<% _.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 = _.f('<% print("hello " + user); %>!');

compiled({ 'user': 'barney' });

// => 'hello barney!'

 

// Use the ES template literal delimiter as an "interpolate" delimiter.

// Disable support by replacing the "interpolate" delimiter.

var compiled = _.f('hello ${ user }!');

compiled({ 'user': 'pebbles' });

// => 'hello pebbles!'

 

// Use backslashes to treat delimiters as plain text.

var compiled = _.f('<%= "\\<%- 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 = _.f(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 = _.f('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 = _.f('hi <%= data.user %>!', { 'variable': 'data' });

compiled.source;

// => function(data) {

//   var __t, __p = '';

//   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';

//   return __p;

// }

 

// Use custom template delimiters.

_.templateSettings.interpolate = /{{([\s\S]+?)}}/g;

var compiled = _.f('hello {{ user }}!');

compiled({ 'user': 'mustache' });

// => 'hello mustache!'

 

// Use the `source` property to inline compiled templates for meaningful

// line numbers in error messages and stack traces.

fs.writeFileSync(path.join(process.cwd(), 'jst.js'), '\

  var JST = {\

    "main": ' + _.f(mainText).source + '\

  };\

');
Term
templateSettings
 Definition
Used to change template delimiters.
Term
templateSettings.escape
 Definition
Used to detect data property values to be HTML-escaped.
Term
templateSettings.evaluate
 Definition
Used to detect code to be evaluated.
Term
templateSettings.imports
 Definition
Used to import variables into the compiled template.
Term
templateSettings.imports._
 Definition
A reference to the lodash function.
Term
templateSettings.interpolate
 Definition
Used to detect data property values to inject.
Term
templateSettings.variable
 Definition
Used to reference the data object in the template text.
Term
throttle
 Definition
// Avoid excessively updating the position while scrolling.
jQuery(window).on('scroll', _.f(updatePosition, 100));

// Invoke `renewToken` when the click event is fired, but not more than once every 5 minutes.
var throttled = _.f(renewToken, 300000, { 'trailing': false });
jQuery(element).on('click', throttled);

// Cancel the trailing throttled invocation.
jQuery(window).on('popstate', throttled.cancel);
Term
thru
 Definition
_(' abc ')
.chain()
.trim()
.f(function(value) {
return [value];
})
.value();
// => ['abc']
Term
times
 Definition
_.f(3, String);
// => ['0', '1', '2']

_.f(4, _.constant(0));
// => [0, 0, 0, 0]
Term
toArray
 Definition
_.f({ 'a': 1, 'b': 2 });
// => [1, 2]

_.f('abc');
// => ['a', 'b', 'c']

_.f(1);
// => []

_.f(null);
// => []
Term
toFinite
 Definition
_.f(3.2);
// => 3.2

_.f(Number.MIN_VALUE);
// => 5e-324

_.f(Infinity);
// => 1.7976931348623157e+308

_.f('3.2');
// => 3.2
Term
toInteger
 Definition
_.f(3.2);
// => 3

_.f(Number.MIN_VALUE);
// => 0

_.f(Infinity);
// => 1.7976931348623157e+308

_.f('3.2');
// => 3
Term
toLength
 Definition
_.f(3.2);
// => 3

_.f(Number.MIN_VALUE);
// => 0

_.f(Infinity);
// => 4294967295

_.f('3.2');
// => 3
Term
toLower
 Definition
_.f('--Foo-Bar--');
// => '--foo-bar--'

_.f('fooBar');
// => 'foobar'

_.f('__FOO_BAR__');
// => '__foo_bar__'
Term
toNumber
 Definition
_.f(3.2);
// => 3.2

_.f(Number.MIN_VALUE);
// => 5e-324

_.f(Infinity);
// => Infinity

_.f('3.2');
// => 3.2
Term
toPairs
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo);
// => [['a', 1], ['b', 2]] (iteration order is not guaranteed)
Term
toPairsIn
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo);
// => [['a', 1], ['b', 2], ['c', 3]] (iteration order is not guaranteed)
Term
toPath
 Definition
_.f('a.b.c');
// => ['a', 'b', 'c']

_.f('a[0].b.c');
// => ['a', '0', 'b', 'c']
Term
toPlainObject
 Definition
function Foo() {
this.b = 2;
}

Foo.prototype.c = 3;

_.assign({ 'a': 1 }, new Foo);
// => { 'a': 1, 'b': 2 }

_.assign({ 'a': 1 }, _.f(new Foo));
// => { 'a': 1, 'b': 2, 'c': 3 }
Term
toSafeInteger
 Definition
_.f(3.2);
// => 3

_.f(Number.MIN_VALUE);
// => 0

_.f(Infinity);
// => 9007199254740991

_.f('3.2');
// => 3
Term
toString
 Definition
_.f(null);
// => ''

_.f(-0);
// => '-0'

_.f([1, 2, 3]);
// => '1,2,3'
Term
toUpper
 Definition
_.f('--foo-bar--');
// => '--FOO-BAR--'

_.f('fooBar');
// => 'FOOBAR'

_.f('__foo_bar__');
// => '__FOO_BAR__'
Term
transform
 Definition
_.f([2, 3, 4], function(result, n) {
result.push(n *= n);
return n % 2 == 0;
}, []);
// => [4, 9]

_.f({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {
(result[value] || (result[value] = [])).push(key);
}, {});
// => { '1': ['a', 'c'], '2': ['b'] }
Term
trim
 Definition
_.f(' abc ');
// => 'abc'

_.f('-_-abc-_-', '_-');
// => 'abc'

_.map([' foo ', ' bar '], _.f);
// => ['foo', 'bar']
Term
trimEnd
 Definition
_.f(' abc ');
// => ' abc'

_.f('-_-abc-_-', '_-');
// => '-_-abc'
Term
trimStart
 Definition
_.f(' abc ');
// => 'abc '

_.f('-_-abc-_-', '_-');
// => 'abc-_-'
Term
truncate
 Definition
_.f('hi-diddly-ho there, neighborino');
// => 'hi-diddly-ho there, neighbo...'

_.f('hi-diddly-ho there, neighborino', {
'length': 24,
'separator': ' '
});
// => 'hi-diddly-ho there,...'

_.f('hi-diddly-ho there, neighborino', {
'length': 24,
'separator': /,? +/
});
// => 'hi-diddly-ho there...'

_.f('hi-diddly-ho there, neighborino', {
'omission': ' [...]'
});
// => 'hi-diddly-ho there, neig [...]'
Term
unary
 Definition
_.map(['6', '8', '10'], _.f(parseInt));
// => [6, 8, 10]
Term
unescape
 Definition
_.f('fred, barney, & pebbles');
// => 'fred, barney, & pebbles'
Term
union
 Definition
_.f([2], [1, 2]);
// => [2, 1]
Term
unionBy
 Definition
_.f([2.1], [1.2, 2.3], Math.floor);
// => [2.1, 1.2]

// The `_.property` iteratee shorthand.
_.f([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 1 }, { 'x': 2 }]
Term
unionWith
 Definition
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.f(objects, others, _.isEqual);
// => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 1 }]
Term
uniq
 Definition
_.f([2, 1, 2]);
// => [2, 1]
Term
uniqBy
 Definition
_.f([2.1, 1.2, 2.3], Math.floor);
// => [2.1, 1.2]

// The `_.property` iteratee shorthand.
_.f([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 1 }, { 'x': 2 }]
Term
uniqWith
 Definition
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.f(objects, _.isEqual);
// => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }]
Term
uniqueId
 Definition
_.f('contact_');
// => 'contact_104'

_.f();
// => '105'
Term
unset
 Definition
var object = { 'a': [{ 'b': { 'c': 7 } }] };
_.f(object, 'a[0].b.c');
// => true

console.log(object);
// => { 'a': [{ 'b': {} }] };

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

console.log(object);
// => { 'a': [{ 'b': {} }] };
Term
unzip
 Definition
var array = [['a', 1, true], ['b', 2, false]];

_.f(array);
// => [['a', 'b'], [1, 2], [true, false]]
Term
unzipWith
 Definition
var array = [[1, 10, 100], [2, 20, 200]];

_.f(array, _.add);
// => [3, 30, 300]
Term
update
 Definition
var object = { 'a': [{ 'b': { 'c': 3 } }] };

_.f(object, 'a[0].b.c', function(n) { return n * n; });
console.log(object.a[0].b.c);
// => 9

_.f(object, 'x[0].y.z', function(n) { return n ? n + 1 : 0; });
console.log(object.x[0].y.z);
// => 0
Term
updateWith
 Definition
var object = {};

_.f(object, '[0][1]', _.constant('a'), Object);
// => { '0': { '1': 'a' } }
Term
upperCase
 Definition
_.f('--foo-bar');
// => 'FOO BAR'

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

_.f('__foo_bar__');
// => 'FOO BAR'
Term
upperFirst
 Definition
_.f('fred');
// => 'Fred'

_.f('FRED');
// => 'FRED'
Term
values
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo);
// => [1, 2] (iteration order is not guaranteed)

_.f('hi');
// => ['h', 'i']
Term
valuesIn
 Definition
function Foo() {
this.a = 1;
this.b = 2;
}

Foo.prototype.c = 3;

_.f(new Foo);
// => [1, 2, 3] (iteration order is not guaranteed)
Term
without
 Definition
_.f([2, 1, 2, 3], 1, 2);
// => [3]
Term
words
 Definition
_.f('fred, barney, & pebbles');
// => ['fred', 'barney', 'pebbles']

_.f('fred, barney, & pebbles', /[^, ]+/g);
// => ['fred', 'barney', '&', 'pebbles']
Term
wrap
 Definition
var p = _.f(_.escape, function(func, text) { return '

' + func(text) + '

'; }); p('fred, barney, & pebbles'); // => '

fred, barney, & pebbles

'
Term
xor
 Definition
_.f([2, 1], [2, 3]);
// => [1, 3]
Term
xorBy
 Definition
_.f([2.1, 1.2], [2.3, 3.4], Math.floor);
// => [1.2, 3.4]

// The `_.property` iteratee shorthand.
_.f([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
// => [{ 'x': 2 }]
Term
xorWith
 Definition
var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.f(objects, others, _.isEqual);
// => [{ 'x': 2, 'y': 1 }, { 'x': 1, 'y': 1 }]
Term
zip
 Definition
_.f(['a', 'b'], [1, 2], [true, false]);
// => [['a', 1, true], ['b', 2, false]]
Term
zipObject
 Definition
_.f(['a', 'b'], [1, 2]);
// => { 'a': 1, 'b': 2 }
Term
zipObjectDeep
 Definition
_.f(['a.b[0].c', 'a.b[1].d'], [1, 2]);
// => { 'a': { 'b': [{ 'c': 1 }, { 'd': 2 }] } }
Term
zipWith
 Definition
_.f([1, 2], [10, 20], [100, 200], function(a, b, c) {
return a + b + c;
});
// => [111, 222]
Supporting users have an ad free experience!