You don't (may not) need Lodash/Underscore
Lodash and Underscore are great modern JavaScript utility libraries, and they are widely used by Front-end developers. However, when you are targeting modern browsers, you may find out that there are many methods which are already supported natively thanks to ECMAScript5 [ES5] and ECMAScript2015 [ES6]. If you want your project to require fewer dependencies, and you know your target browser clearly, then you may not need Lodash/Underscore.
You are welcome to contribute with more items provided below.
-
If you are targeting legacy JavaScript engine with those ES5 methods, you can use es5-shim
-
Please note that, the examples used below are just showing you the native alternative of performing certain tasks. For some functions, Lodash provides you more options than native built-ins. This list is not a 1:1 comparison.
-
Please send a PR if you want to add or modify the code. No need to open an issue unless it's something big and you want to discuss.
Voice of Developers
Make use of native JavaScript object and array utilities before going big.
—Cody Lindley, Author of jQuery Cookbook and JavaScript Enlightenment
You probably don't need Lodash. Nice List of JavaScript methods which you can use natively.
—Daniel Lamb, Computer Scientist, Technical Reviewer of Secrets of the JavaScript Ninja and Functional Programming in JavaScript
—Tero Parviainen, Author of build-your-own-angular
I'll admit, I've been guilty of overusing #lodash. Excellent resource.
—@therebelrobot, Maker of web things, Facilitator for Node.js/io.js
ESLint Plugin
If you're using ESLint, you can install a plugin that will help you identify places in your codebase where you don't (may not) need Lodash/Underscore.
Install the plugin...
npm install --save-dev eslint-plugin-you-dont-need-lodash-underscore
...then update your config
"extends" : ["plugin:you-dont-need-lodash-underscore/compatible"],
For more information, see Configuring the ESLint Plugin
Quick Links
- _.chunk
- _.compact
- _.concat
- _.difference
- _.drop
- _.dropRight
- _.fill
- _.find
- _.findIndex
- _.first
- _.flatten
- _.flattenDeep
- _.fromPairs
- _.head and _.tail
- _.indexOf
- _.intersection
- _.isArray
- _.isArrayBuffer
- _.join
- _.last
- _.lastIndexOf
- _.reverse
- _.slice
- _.without
- _.initial
- _.pull
- _.unionBy
- _.each
- _.every
- _.filter
- _.groupBy
- _.includes
- _.keyBy
- _.map
- _.minBy and _.maxBy
- _.orderBy
- _.pluck
- _.range
- _.reduce
- _.reduceRight
- _.reject
- _.size
- _.some
- _.sortBy
- _.uniq
- _.uniqWith
- _.castArray
- _.gt
- _.gte
- _.isDate
- _.isEmpty
- _.isFinite
- _.isInteger
- _.isNaN
- _.isNil
- _.isNull
- _.isUndefined
- _.capitalize
- _.endsWith
- _.isString
- _.lowerFirst
- _.padStart and _.padEnd
- _.repeat
- _.replace
- _.split
- _.startsWith
- _.template
- _.toLower
- _.toUpper
- _.trim
- _.upperFirst
Array
_.chunk
Creates an array of elements split into groups the length of size.
// Underscore/Lodash
_.chunk(['a', 'b', 'c', 'd'], 2);
// => [['a', 'b'], ['c', 'd']]
_.chunk(['a', 'b', 'c', 'd'], 3);
// => [['a', 'b', 'c'], ['d']]
// Native
const chunk = (input, size) => {
return input.reduce((arr, item, idx) => {
return idx % size === 0
? [...arr, [item]]
: [...arr.slice(0, -1), [...arr.slice(-1)[0], item]];
}, []);
};
chunk(['a', 'b', 'c', 'd'], 2);
// => [['a', 'b'], ['c', 'd']]
chunk(['a', 'b', 'c', 'd'], 3);
// => [['a', 'b', 'c'], ['d']]
Browser Support for Spread in array literals
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46.0 |
12.0 |
16.0 |
37.0 |
8.0 |
_.compact
Creates an array with all falsy values removed.
// Underscore/Lodash
_.compact([0, 1, false, 2, '', 3]);
// output: [1, 2, 3]
// Native
[0, 1, false, 2, '', 3].filter(Boolean)
// output: [1, 2, 3]
array.prototype.filter
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1.5 |
9.0 |
_.concat
Creates a new array concatenating array with any additional arrays and/or values.
// Underscore/Lodash
var array = [1]
var other = _.concat(array, 2, [3], [[4]])
console.log(other)
// output: [1, 2, 3, [4]]
// Native
var array = [1]
var other = array.concat(2, [3], [[4]])
console.log(other)
// output: [1, 2, 3, [4]]
Array.prototype.concat()
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1.0 |
1.0 |
5.5 |
_.difference
Similar to without, but returns the values from array that are not present in the other arrays.
// Underscore/Lodash
console.log(_.difference([1, 2, 3, 4, 5], [5, 2, 10]))
// output: [1, 3, 4]
// Native
var arrays = [[1, 2, 3, 4, 5], [5, 2, 10]];
console.log(arrays.reduce(function(a, b) {
return a.filter(function(value) {
return !b.includes(value);
});
}));
// output: [1, 3, 4]
// ES6
let arrays = [[1, 2, 3, 4, 5], [5, 2, 10]];
console.log(arrays.reduce((a, b) => a.filter(c => !b.includes(c))));
// output: [1, 3, 4]
Array.prototype.reduce()
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3.0 |
9.0 |
10.5 |
4.0 |
_.drop
Creates a slice of array with n elements dropped from the beginning.
// Underscore/Lodash
_.drop([1, 2, 3]);
// => [2, 3]
_.drop([1, 2, 3], 2);
// => [3]
// Native
[1, 2, 3].slice(1);
// => [2, 3]
[1, 2, 3].slice(2);
// => [3]
Array.prototype.slice()
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1.0 |
_.dropRight
Creates a slice of array with n elements dropped at the end.
// Underscore/Lodash
_.dropRight([1, 2, 3]);
// => [1, 2]
_.dropRight([1, 2, 3], 2);
// => [1]
// Native
[1, 2, 3].slice(0, -1);
// => [1, 2]
[1, 2, 3].slice(0, -2);
// => [1]
Array.prototype.slice()
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1.0 |
_.fill
Fills elements of array with value from start up to, but not including, end.
Note that fill
is a mutable method in both native and Lodash/Underscore.
// Underscore/Lodash
var array = [1, 2, 3]
_.fill(array, 'a')
console.log(array)
// output: ['a', 'a', 'a']
_.fill(Array(3), 2)
// output: [2, 2, 2]
_.fill([4, 6, 8, 10], '*', 1, 3)
// output: [4, '*', '*', 10]
// Native
var array = [1, 2, 3]
array.fill('a')
console.log(array)
// output: ['a', 'a', 'a']
Array(3).fill(2)
// output: [2, 2, 2]
[4, 6, 8, 10].fill('*', 1, 3)
// output: [4, '*', '*', 10]
Array.prototype.fill()
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45.0 |
31.0 |
32.0 |
8 |
_.find
Returns the value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned.
// Underscore/Lodash
var users = [
{ 'user': 'barney', 'age': 36, 'active': true },
{ 'user': 'fred', 'age': 40, 'active': false },
{ 'user': 'pebbles', 'age': 1, 'active': true }
]
_.find(users, function (o) { return o.age < 40; })
// output: object for 'barney'
// Native
var users = [
{ 'user': 'barney', 'age': 36, 'active': true },
{ 'user': 'fred', 'age': 40, 'active': false },
{ 'user': 'pebbles', 'age': 1, 'active': true }
]
users.find(function (o) { return o.age < 40; })
// output: object for 'barney'
Array.prototype.find()
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45.0 |
25.0 |
32.0 |
7.1 |
_.findIndex
Returns the index of the first element in the array that satisfies the provided testing function. Otherwise -1 is returned.
// Underscore/Lodash
var users = [
{ 'user': 'barney', 'age': 36, 'active': true },
{ 'user': 'fred', 'age': 40, 'active': false },
{ 'user': 'pebbles', 'age': 1, 'active': true }
]
var index = _.findIndex(users, function (o) { return o.age >= 40; })
console.log(index)
// output: 1
// Native
var users = [
{ 'user': 'barney', 'age': 36, 'active': true },
{ 'user': 'fred', 'age': 40, 'active': false },
{ 'user': 'pebbles', 'age': 1, 'active': true }
]
var index = users.findIndex(function (o) { return o.age >= 40; })
console.log(index)
// output: 1
Array.prototype.findIndex()
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32.0 |
7.1 |
_.first
Returns the first element of an array. Passing n will return the first n elements of the array.
// Underscore/Lodash
_.first([1, 2, 3, 4, 5]);
// => 1
// Underscore
_.first([1, 2, 3, 4, 5], 2);
// => [1, 2]
// Native
[1, 2, 3, 4, 5][0];
// => 1
//or
[].concat(1, 2, 3, 4, 5).shift()
// => 1
//or
[].concat([1, 2, 3, 4, 5]).shift()
// => 1
// Native (works even with potentially undefined/null, like _.first)
[].concat(undefined).shift()
// => undefined
[1, 2, 3, 4, 5].slice(0, 2);
// => [1, 2]
Array.prototype.slice()
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1.0 |
1.0 |
_.flatten
Flattens array a single level deep.
// Underscore/Lodash
_.flatten([1, [2, [3, [4]], 5]]);
// => [1, 2, [3, [4]], 5]
// Native
const flatten = [1, [2, [3, [4]], 5]].reduce( (a, b) => a.concat(b), [])
// => [1, 2, [3, [4]], 5]
const flatten = [].concat(...[1, [2, [3, [4]], 5]])
// => [1, 2, [3, [4]], 5]
// Native(ES2019)
const flatten = [1, [2, [3, [4]], 5]].flat()
// => [1, 2, [3, [4]], 5]
const flatten = [1, [2, [3, [4]], 5]].flatMap(number => number)
// => [1, 2, [3, [4]], 5]
Array.prototype.reduce()
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9.0 |
10.5 |
4 |
Array.prototype.flat()
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56 |
12 |
Array.prototype.flatMap()
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56 |
12 |
_.flattenDeep
Recursively flattens array.
// Underscore/Lodash
_.flattenDeep([1, [2, [3, [4]], 5]]);
// => [1, 2, 3, 4, 5]
// Native
const flattenDeep = (arr) => Array.isArray(arr)
? arr.reduce( (a, b) => a.concat(flattenDeep(b)) , [])
: [arr]
flattenDeep([1, [[2], [3, [4]], 5]])
// => [1, 2, 3, 4, 5]
// Native(ES2019)
[1, [2, [3, [4]], 5]].flat(Infinity)
// => [1, 2, 3, 4, 5]
const flattenDeep = (arr) => arr.flatMap((subArray, index) => Array.isArray(subArray) ? flattenDeep(subArray) : subArray)
flattenDeep([1, [[2], [3, [4]], 5]])
// => [1, 2, 3, 4, 5]
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37.0 |
7.1 |
Array.prototype.flat()
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62 |
56 |
12 |
Array.prototype.flatMap()
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62 |
56 |
12 |
_.fromPairs
Returns an object composed from key-value pairs.
// Underscore/Lodash
_.fromPairs([['a', 1], ['b', 2]]);
// => { 'a': 1, 'b': 2 }
// Native
const fromPairs = function(arr) {
return arr.reduce(function(accumulator, value) {
accumulator[value[0]] = value[1];
return accumulator;
}, {})
}
// Compact form
const fromPairs = (arr) => arr.reduce((acc, val) => (acc[val[0]] = val[1], acc), {})
fromPairs([['a', 1], ['b', 2]]);
// => { 'a': 1, 'b': 2 }
// Native(ES2019)
Object.fromEntries([['a', 1], ['b', 2]])
// => { 'a': 1, 'b': 2 }
Array.prototype.reduce()
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9.0 |
10.5 |
4.0 |
Object.fromEntries()
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73.0 |
79.0 |
63.0 |
60 |
12.1 |
_.head and _.tail
Gets the first element or all but the first element.
const array = [1, 2, 3]
// Underscore: _.first, _.head, _.take
// Lodash: _.first, _.head
_.head(array)
// output: 1
// Underscore: _.rest, _.tail, _.drop
// Lodash: _.tail
_.tail(array)
// output: [2, 3]
// Native
const [ head, ...tail ] = array
console.log(head)
// output: 1
console.log(tail)
// output [2, 3]
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37.0 |
8.0 |
_.indexOf
Returns the first index at which a given element can be found in the array, or -1 if it is not present.
// Underscore/Lodash
var array = [2, 9, 9]
var result = _.indexOf(array, 2)
console.log(result)
// output: 0
// Native
var array = [2, 9, 9]
var result = array.indexOf(2)
console.log(result)
// output: 0
Array.prototype.indexOf()
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_.intersection
Returns an array that is the intersection of all the arrays. Each value in the result is present in each of the arrays.
// Underscore/Lodash
console.log(_.intersection([1, 2, 3], [101, 2, 1, 10], [2, 1]))
// output: [1, 2]
// Native
var arrays = [[1, 2, 3], [101, 2, 1, 10], [2, 1]];
console.log(arrays.reduce(function(a, b) {
return a.filter(function(value) {
return b.includes(value);
});
}));
// output: [1, 2]
// ES6
let arrays = [[1, 2, 3], [101, 2, 1, 10], [2, 1]];
console.log(arrays.reduce((a, b) => a.filter(c => b.includes(c))));
// output: [1, 2]
Array.prototype.reduce()
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4.0 |
_.takeRight
Creates a slice of array with n elements taken from the end.
Lodash
method. See example below to understand why.
// Underscore/Lodash
_.takeRight([1, 2, 3]);
// => [3]
_.takeRight([1, 2, 3], 2);
// => [2, 3]
_.takeRight([1, 2, 3], 5);
// => [1, 2, 3]
// Native
[1, 2, 3].slice(-1);
// => [3]
[1, 2, 3].slice(-2);
// => [2, 3]
[1, 2, 3].slice(-5);
// => [1, 2, 3]
// Difference in compatibility
// Lodash
_.takeRight([1, 2, 3], 0);
// => []
// Native
[1, 2, 3].slice(0);
// => [1, 2, 3]
Array.prototype.slice()
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1.0 |
1.0 |
_.isArray
Returns true if given value is an array.
// Lodash
var array = []
console.log(_.isArray(array))
// output: true
// Native
var array = []
console.log(Array.isArray(array));
// output: true
Array.isArray()
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4.0 |
9.0 |
10.5 |
5.0 |
_.isArrayBuffer
Checks if value is classified as an ArrayBuffer object.
// Lodash
_.isArrayBuffer(new ArrayBuffer(2));
// output: true
// Native
console.log(new ArrayBuffer(2) instanceof ArrayBuffer);
// output: true
ArrayBuffer
from another realm. See details.
instanceof
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_.join
Not in Underscore.js
Joins a list of elements in an array with a given separator.
// Lodash
var result = _.join(['one', 'two', 'three'], '--')
console.log(result)
// output: 'one--two--three'
// Native
var result = ['one', 'two', 'three'].join('--')
console.log(result)
// output: 'one--two--three'
Array.prototype.join()
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_.last
Returns the last element of an array. Passing n will return the last n elements of the array.
// Underscore/Lodash
const numbers = [1, 2, 3, 4, 5];
_.last(numbers);
// => 5
// Underscore
_.last(numbers, 2);
// => [4, 5]
// Native
const numbers = [1, 2, 3, 4, 5];
numbers[numbers.length - 1];
// => 5
//or
numbers.slice(-1)[0];
// => 5
//or
[].concat(numbers).pop()
// => 5
//or
numbers.at(-1);
// => 5
// Native (works even with potentially undefined/null)
[].concat(undefined).pop()
// => undefined
numbers.slice(-2);
// => [4, 5]
Array.prototype.concat()
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Array.prototype.at()
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_.lastIndexOf
Returns the index of the last occurrence of value in the array, or -1 if value is not present.
// Underscore/Lodash
var array = [2, 9, 9, 4, 3, 6]
var result = _.lastIndexOf(array, 9)
console.log(result)
// output: 2
// Native
var array = [2, 9, 9, 4, 3, 6]
var result = array.lastIndexOf(9)
console.log(result)
// output: 2
Array.prototype.lastIndexOf()
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_.reverse
Not in Underscore.js
Reverses array so that the first element becomes the last, the second element becomes the second to last, and so on.
// Lodash
var array = [1, 2, 3]
console.log(_.reverse(array))
// output: [3, 2, 1]
// Native
var array = [1, 2, 3]
console.log(array.reverse())
// output: [3, 2, 1]
Voice from the Lodash author:
Lodash's
_.reverse
just callsArray#reverse
and enables composition like_.map(arrays, _.reverse).
It's exposed on _ because previously, likeUnderscore
, it was only exposed in the chaining syntax. --- jdalton
Array.prototype.reverse()
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_.slice
Returns a shallow copy of a portion of an array into a new array object selected from begin
to end
(end
not included)
// Lodash
var array = [1, 2, 3, 4]
console.log(_.slice(array, 1, 3))
// output: [2, 3]
// Native
var array = [1, 2, 3, 4]
console.log(array.slice(1, 3));
// output: [2, 3]
Array.prototype.slice()
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_.without
Not in Underscore.js
Returns an array where matching items are filtered.
// Lodash
var array = [1, 2, 3]
console.log(_.without(array, 2))
// output: [1, 3]
// Native
var array = [1, 2, 3]
console.log(array.filter(function(value) {
return value !== 2;
}));
// output: [1, 3]
Array.prototype.filter()
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_.initial
Returns everything but the last entry of the array. Pass n to exclude the last n elements from the result.
// Underscore
var array = [5, 4, 3, 2, 1]
console.log(_.initial(array, 2))
// output: [5, 4, 3]
// Native
var array = [5, 4, 3, 2, 1]
console.log(array.slice(0, -2));
// output: [5, 4, 3]
Array.prototype.slice()
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_.pull
Removes all provided values from the given array using strict equality for comparisons, i.e. ===.
// Lodash
const array = [1, 2, 3, 1, 2, 3];
_.pull(array, 2, 3);
console.log(array); // output: [1, 1]
// Native JS
const array = [1, 2, 3, 1, 2, 3];
function pull(arr, ...removeList){
var removeSet = new Set(removeList)
return arr.filter(function(el){
return !removeSet.has(el)
})
}
console.log(pull(array, 2, 3)); // output: [1, 1]
console.log(array); // still [1, 2, 3, 1, 2, 3]. This is not in place, unlike lodash!
// TypeScript
const array = [1, 2, 3, 1, 2, 3];
const pull = <T extends unknown>(sourceArray: T[], ...removeList: T[]): T[] => {
const removeSet = new Set(removeList);
return sourceArray.filter(el => !removeSet.has(el));
};
console.log(pull(array, 2, 3)); // output: [1, 1]
console.log(array); // still [1, 2, 3, 1, 2, 3]. This is not in place, unlike lodash!
Array.prototype.filter()
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Set.prototype.has()
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38 |
12 |
13 |
11 |
25 |
8 |
_.unionBy
Creates an array of unique values, taking an iteratee
to compute uniqueness with
(note that to iterate by a key in an object you must use x => x.key
instead of key
for the iteratee
)
// Lodash
var array1 = [2.1];
var array2 = [1.2, 2.3];
var result = _.unionBy(array1, array2, Math.floor)
console.log(result)
// output: [2.1, 1.2]
// Native
var array1 = [2.1];
var array2 = [1.2, 2.3];
function unionBy(...arrays) {
const iteratee = (arrays).pop();
if (Array.isArray(iteratee)) {
return []; // return empty if iteratee is missing
}
return [...arrays].flat().filter(
(set => (o) => set.has(iteratee(o)) ? false : set.add(iteratee(o)))(new Set()),
);
};
console.log(unionBy(array1, array2, Math.floor))
// output: [2.1, 1.2]
Array.prototype.flat()
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69 |
62 |
56 |
12 |
Array.isArray()
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5.0 |
4.0 |
9.0 |
10.5 |
5.0 |
Set.prototype.has()
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38 |
12 |
13 |
11 |
25 |
8 |
Collection*
_.each
Iterates over a list of elements, yielding each in turn to an iteratee function.
// Underscore/Lodash
//For arrays
_.each([1, 2, 3], function (value, index) {
console.log(value)
})
// output: 1 2 3
//For objects
_.each({'one':1, 'two':2, 'three':3}, function(value) {
console.log(value)
})
// output: 1 2 3
// Native
//For arrays
[1, 2, 3].forEach(function (value, index) {
console.log(value)
})
// output: 1 2 3
//For objects
Object.entries({'one':1, 'two':2, 'three':3}).forEach(function([key,value],index) {
console.log(value)
})
//output: 1 2 3
Array.prototype.forEach()
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9.0 |
Object.entries().forEach()
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54 |
14 |
47 |
41 |
10.1 |
_.every
Tests whether all elements in the array pass the test implemented by the provided function.
// Underscore/Lodash
function isLargerThanTen (element, index, array) {
return element >= 10
}
var array = [10, 20, 30]
var result = _.every(array, isLargerThanTen)
console.log(result)
// output: true
// Native
function isLargerThanTen (element, index, array) {
return element >= 10
}
var array = [10, 20, 30]
var result = array.every(isLargerThanTen)
console.log(result)
// output: true
Array.prototype.every()
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1.5 |
9.0 |
_.filter
Creates a new array with all elements that pass the test implemented by the provided function.
// Underscore/Lodash
function isBigEnough (value) {
return value >= 10
}
var array = [12, 5, 8, 130, 44]
var filtered = _.filter(array, isBigEnough)
console.log(filtered)
// output: [12, 130, 44]
// Native
function isBigEnough (value) {
return value >= 10
}
var array = [12, 5, 8, 130, 44]
var filtered = array.filter(isBigEnough)
console.log(filtered)
// output: [12, 130, 44]
Array.prototype.filter()
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1.5 |
9 |
_.groupBy
Group items by key.
// Underscore/Lodash
var grouped = _.groupBy(['one', 'two', 'three'], 'length')
console.log(grouped)
// output: {3: ["one", "two"], 5: ["three"]}
// Native
var grouped = ['one', 'two', 'three'].reduce((r, v, i, a, k = v.length) => ((r[k] || (r[k] = [])).push(v), r), {})
console.log(grouped)
// output: {3: ["one", "two"], 5: ["three"]}
// Underscore/Lodash
var grouped = _.groupBy([1.3, 2.1, 2.4], num => Math.floor(num))
console.log(grouped)
// output: {1: [1.3], 2: [2.1, 2.4]}
// Native
var grouped = [1.3, 2.1, 2.4].reduce((r, v, i, a, k = Math.floor(v)) => ((r[k] || (r[k] = [])).push(v), r), {})
console.log(grouped)
// output: {1: [1.3], 2: [2.1, 2.4]}
Array.prototype.reduce()
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3.0 |
9.0 |
10.5 |
4.0 |
_.includes
Checks if a value is in collection.
var array = [1, 2, 3]
// Underscore/Lodash - also called _.contains
_.includes(array, 1)
// output: true
// Native
var array = [1, 2, 3]
array.includes(1)
// output: true
// Native (does not use same value zero)
var array = [1, 2, 3]
array.indexOf(1) > -1
// output: true
Array.prototype.includes
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47.0 |
14.0 |
43.0 |
34.0 |
9.0 |
Array.prototype.indexOf
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1.5 |
9.0 |
_.keyBy
Not in Underscore.js
Creates an object composed of keys generated from the results of running each element of collection through iteratee.
// Lodash
console.log(_.keyBy(['a', 'b', 'c']))
// output: { a: 'a', b: 'b', c: 'c' }
console.log(_.keyBy([{ id: 'a1', title: 'abc' }, { id: 'b2', title: 'def' }], 'id'))
// output: { a1: { id: 'a1', title: 'abc' }, b2: { id: 'b2', title: 'def' } }
console.log(_.keyBy({ data: { id: 'a1', title: 'abc' }}, 'id'))
// output: { a1: { id: 'a1', title: 'abc' }}
// keyBy for array only
const keyBy = (array, key) => (array || []).reduce((r, x) => ({ ...r, [key ? x[key] : x]: x }), {});
// Native
console.log(keyBy(['a', 'b', 'c']))
// output: { a: 'a', b: 'b', c: 'c' }
console.log(keyBy([{ id: 'a1', title: 'abc' }, { id: 'b2', title: 'def' }], 'id'))
// output: { a1: { id: 'a1', title: 'abc' }, b2: { id: 'b2', title: 'def' } }
console.log(keyBy(Object.values({ data: { id: 'a1', title: 'abc' }}), 'id'))
// output: { a1: { id: 'a1', title: 'abc' }}
// keyBy for array and object
const collectionKeyBy = (collection, key) => {
const c = collection || {};
return c.isArray() ? keyBy(c, key) : keyBy(Object.values(c), key);
}
Array.prototype.reduce()
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12.0 |
3.0 |
9.0 |
10.5 |
4.0 |
_.map
Translates all items in an array or object to new array of items.
// Underscore/Lodash
var array1 = [1, 2, 3]
var array2 = _.map(array1, function (value, index) {
return value * 2
})
console.log(array2)
// output: [2, 4, 6]
// Native
var array1 = [1, 2, 3]
var array2 = array1.map(function (value, index) {
return value * 2
})
console.log(array2)
// output: [2, 4, 6]
// Underscore/Lodash
var object1 = { 'a': 1, 'b': 2, 'c': 3 }
var object2 = _.map(object1, function (value, index) {
return value * 2
})
console.log(object2)
// output: [2, 4, 6]
// Native
var object1 = { 'a': 1, 'b': 2, 'c': 3 }
var object2 = Object.entries(object1).map(function ([key, value], index) {
return value * 2
})
console.log(object2)
// output: [2, 4, 6]
Object.entries()
and destructuring
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Array.prototype.map()
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9.0 |
_.minBy and _.maxBy
Use Array#reduce for find the maximum or minimum collection item
// Underscore/Lodash
var data = [{ value: 6 }, { value: 2 }, { value: 4 }]
var minItem = _.minBy(data, 'value')
var maxItem = _.maxBy(data, 'value')
console.log(minItem, maxItem)
// output: { value: 2 } { value: 6 }
// Native
var data = [{ value: 6 }, { value: 2 }, { value: 4 }]
var minItem = data.reduce(function(a, b) { return a.value <= b.value ? a : b }, {})
var maxItem = data.reduce(function(a, b) { return a.value >= b.value ? a : b }, {})
console.log(minItem, maxItem)
// output: { value: 2 }, { value: 6 }
Extract a functor and use es2015 for better code
// utils
const makeSelect = (comparator) => (a, b) => comparator(a, b) ? a : b
const minByValue = makeSelect((a, b) => a.value <= b.value)
const maxByValue = makeSelect((a, b) => a.value >= b.value)
// main logic
const data = [{ value: 6 }, { value: 2 }, { value: 4 }]
const minItem = data.reduce(minByValue, {})
const maxItem = data.reduce(maxByValue, {})
console.log(minItem, maxItem)
// output: { value: 2 }, { value: 6 }
// or also more universal and little slower variant of minBy
const minBy = (collection, key) => {
// slower because need to create a lambda function for each call...
const select = (a, b) => a[key] <= b[key] ? a : b
return collection.reduce(select, {})
}
console.log(minBy(data, 'value'))
// output: { value: 2 }
Array.prototype.reduce()
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3.0 |
9.0 |
10.5 |
4.0 |
_.pluck
array.map
or _.map
can also be used to replace _.pluck
. Lodash v4.0 removed _.pluck
in favor of _.map
with iteratee shorthand. Details can be found in Changelog
// Underscore/Lodash
var array1 = [{name: "Alice"}, {name: "Bob"}, {name: "Jeremy"}]
var names = _.pluck(array1, "name")
console.log(names)
// output: ["Alice", "Bob", "Jeremy"]
// Native
var array1 = [{name: "Alice"}, {name: "Bob"}, {name: "Jeremy"}]
var names = array1.map(function(x){
return x.name
})
console.log(names)
// output: ["Alice", "Bob", "Jeremy"]
Array.prototype.map()
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9.0 |
_.reduce
Applies a function against an accumulator and each value of the array (from left-to-right) to reduce it to a single value.
// Underscore/Lodash
var array = [0, 1, 2, 3, 4]
var result = _.reduce(array, function (previousValue, currentValue, currentIndex, array) {
return previousValue + currentValue
})
console.log(result)
// output: 10
// Native
var array = [0, 1, 2, 3, 4]
var result = array.reduce(function (previousValue, currentValue, currentIndex, array) {
return previousValue + currentValue
})
console.log(result)
// output: 10
Array.prototype.reduce()
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3.0 |
9.0 |
10.5 |
4.0 |
_.range
Creates an array of numbers progressing from start up to.
// Underscore/Lodash
_.range(4) // output: [0, 1, 2, 3]
_.range(-4) // output: [0, -1, -2, -3]
_.range(1, 5) // output: [1, 2, 3, 4]
_.range(0, 20, 5) // output: [0, 5, 10, 15]
// Native ( solution with Array.from )
Array.from({length: 4}, (_, i) => i) // output: [0, 1, 2, 3]
Array.from({length: 4}, (_, i) => -i) // output: [-0, -1, -2, -3]
Array.from({length: 4}, (_, i) => i + 1) // output: [1, 2, 3, 4]
Array.from({length: 4}, (_, i) => i * 5) // output: [0, 5, 10, 15]
// Native ( solution with keys() and spread )
[...Array(4).keys()] // output: [0, 1, 2, 3]
[...Array(4).keys()].map(k => -k) // output: [-0, -1, -2, -3]
[...Array(4).keys()].map(k => k + 1) // output: [1, 2, 3, 4]
[...Array(4).keys()].map(k => k * 5) // output: [0, 5, 10, 15]
Array.from()
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32.0 |
9.0 |
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46.0 |
12.0 |
16.0 |
37.0 |
7.1 |
_.reduceRight
This method is like _.reduce except that it iterates over elements of collection from right to left.
// Underscore/Lodash
var array = [0, 1, 2, 3, 4]
var result = _.reduceRight(array, function (previousValue, currentValue, currentIndex, array) {
return previousValue - currentValue
})
console.log(result)
// output: -2
// Native
var array = [0, 1, 2, 3, 4]
var result = array.reduceRight(function (previousValue, currentValue, currentIndex, array) {
return previousValue - currentValue
})
console.log(result)
// output: -2
Array.prototype.reduceRight()
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3.0 |
9.0 |
10.5 |
4.0 |
_.reject
The opposite of _.filter; this method returns the elements of collection that predicate does not return truthy for.
// Underscore/Lodash
var array = [1, 2, 3, 4, 5];
var result = _.reject(array, function (x) {
return x % 2 === 0;
});
// output: [1, 3, 5]
// Native
var array = [1, 2, 3, 4, 5];
var reject = function (arr, predicate) {
var complement = function (f) {
return function (x) {
return !f(x);
}
};
return arr.filter(complement(predicate));
};
// output: [1, 3, 5]
Array.prototype.filter()
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1.5 |
9.0 |
9.5 |
3.0 |
_.sample
Gets a random element from array
.
// Underscore/Lodash
const array = [0, 1, 2, 3, 4]
const result = _.sample(array)
console.log(result)
// output: 2
// Native
const array = [0, 1, 2, 3, 4]
const sample = arr => {
const len = arr == null ? 0 : arr.length
return len ? arr[Math.floor(Math.random() * len)] : undefined
}
const result = sample(array)
console.log(result)
// output: 2
Array.prototype.length()
and Math.random()
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1.0 |
_.size
Returns the number of values in the collection.
// Underscore/Lodash
var result = _.size({one: 1, two: 2, three: 3})
console.log(result)
// output: 3
// Native
var result2 = Object.keys({one: 1, two: 2, three: 3}).length
console.log(result2)
// output: 3
Object.keys()
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5.0 |
4.0 |
9.0 |
12.0 |
5.0 |
_.some
Tests whether any of the elements in the array pass the test implemented by the provided function.
// Underscore/Lodash
function isLargerThanTen (element, index, array) {
return element >= 10
}
var array = [10, 9, 8]
var result = _.some(array, isLargerThanTen)
console.log(result)
// output: true
// Native
function isLargerThanTen (element, index, array) {
return element >= 10
}
var array = [10, 9, 8]
var result = array.some(isLargerThanTen)
console.log(result)
// output: true
Array.prototype.some()
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1.5 |
_.sortBy and _.orderBy
Sorts an array of object based on an object key provided by a parameter (note this is more limited than Underscore/Lodash).
const fruits = [
{name:"banana", amount: 2},
{name:"apple", amount: 4},
{name:"pineapple", amount: 2},
{name:"mango", amount: 1}
];
// Underscore
_.sortBy(fruits, 'name');
// => [{name:"apple", amount: 4}, {name:"banana", amount: 2}, {name:"mango", amount: 1}, {name:"pineapple", amount: 2}]
// Lodash
_.orderBy(fruits, ['name'],['asc']);
// => [{name:"apple", amount: 4}, {name:"banana", amount: 2}, {name:"mango", amount: 1}, {name:"pineapple", amount: 2}]
// Native
const sortBy = (key) => {
return (a, b) => (a[key] > b[key]) ? 1 : ((b[key] > a[key]) ? -1 : 0);
};
// The native sort modifies the array in place. `_.orderBy` and `_.sortBy` do not, so we use `.concat()` to
// copy the array, then sort.
fruits.concat().sort(sortBy("name"));
// => [{name:"apple", amount: 4}, {name:"banana", amount: 2}, {name:"mango", amount: 1}, {name:"pineapple", amount: 2}]
Array.prototype.concat()
and Array.prototype.sort()
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1.0 |
5.5 |
_.uniq
Produces a duplicate-free version of the array, using === to test object equality.
// Underscore/Lodash
var array = [1, 2, 1, 4, 1, 3]
var result = _.uniq(array)
console.log(result)
// output: [1, 2, 4, 3]
// Native
var array = [1, 2, 1, 4, 1, 3];
var result = [...new Set(array)];
console.log(result)
// output: [1, 2, 4, 3]
Browser Support for Spread in array literals
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46.0 |
12.0 |
16.0 |
37.0 |
8.0 |
Function
_.after
Note this is an alternative implementation
Creates a version of the function that will only be run after first being called count times. Useful for grouping asynchronous responses, where you want to be sure that all the async calls have finished, before proceeding.
var notes = ['profile', 'settings']
// Underscore/Lodash
var renderNotes = _.after(notes.length, render)
notes.forEach(function (note) {
console.log(note)
renderNotes()
})
// Native
notes.forEach(function (note, index) {
console.log(note)
if (notes.length === (index + 1)) {
render()
}
})
Array.prototype.forEach()
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9.0 |
_.bind
Create a new function that calls func with thisArg and args.
var objA = {
x: 66,
offsetX: function(offset) {
return this.x + offset;
}
}
var objB = {
x: 67
};
// Underscore/Lodash
var boundOffsetX = _.bind(objA.offsetX, objB, 0);
// Native
var boundOffsetX = objA.offsetX.bind(objB, 0);
Function.prototype.bind()
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7.0 |
4.0 |
9.0 |
11.6 |
5.1 |
_.isFunction
Checks if value is classified as a Function object.
// Lodash
_.isFunction(console.log);
// => true
_.isFunction(/abc/);
// => false
// Native
function isFunction(func) {
return typeof func === "function";
}
isFunction(setTimeout);
// => true
isFunction(123);
// => false
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_.debounce
Create a new function that calls func with thisArg and args.
function debounce(func, wait, immediate) {
var timeout;
return function() {
var context = this, args = arguments;
clearTimeout(timeout);
timeout = setTimeout(function() {
timeout = null;
if (!immediate) func.apply(context, args);
}, wait);
if (immediate && !timeout) func.apply(context, args);
};
}
// Avoid costly calculations while the window size is in flux.
jQuery(window).on('resize', debounce(calculateLayout, 150));
debounce
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7.0 |
4.0 |
9.0 |
11.6 |
5.1 |
_.partial
Create a new function that calls func with args.
// Lodash
function greet(greeting, name) {
return greeting + ' ' + name;
}
var sayHelloTo = _.partial(greet, 'Hello');
var result = sayHelloTo('Jose')
console.log(result)
// output: 'Hello Jose'
// Native
function greet(greeting, name) {
return greeting + ' ' + name;
}
var sayHelloTo = (...args) => greet('Hello', ...args)
var result = sayHelloTo('Jose')
console.log(result)
// output: 'Hello Jose'
// Native
const partial = (func, ...boundArgs) => (...remainingArgs) => func(...boundArgs, ...remainingArgs)
var sayHelloTo = partial(greet, 'Hello');
var result = sayHelloTo('Jose')
console.log(result)
// output: 'Hello Jose'
Browser Support for Spread
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46.0 |
12.0 |
16.0 |
37.0 |
8.0 |
_.throttle
Create a new function that limits calls to func to once every given timeframe.
function throttle(func, timeFrame) {
var lastTime = 0;
return function (...args) {
var now = new Date();
if (now - lastTime >= timeFrame) {
func(...args);
lastTime = now;
}
};
}
// Avoid running the same function twice within the specified timeframe.
jQuery(window).on('resize', throttle(calculateLayout, 150));
throttle
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5.0 |
12.0 |
3.0 |
9.0 |
10.5 |
4.0 |
Lang
_.castArray
Puts the value into an array of length one if it is not already an array.
// Underscore
console.log(_.castArray(5))
// output: [5]
console.log(_.castArray([2]))
// output: [2]
// Native
function castArray(arr) {
return Array.isArray(arr) ? arr : [arr]
}
// output: true
console.log(castArray(5));
// output: [5]
console.log(castArray([2]));
// output: [2]
Array.isArray()
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5.0 |
4.0 |
9.0 |
10.5 |
5.0 |
_.isDate
Checks if value is classified as a Date object.
// Lodash
console.log(_.isDate(new Date));
// output: true
// Native
console.log(Object.prototype.toString.call(new Date) === "[object Date]");
// output: true
String.prototype.toString.call()
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_.gt
Checks if value is greater than other.
// Lodash
console.log(_.gt(3, 1))
// output: true
// Native
console.log(3 > 1);
// output: true
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_.gte
Checks if value is greater than or equal to other.
// Lodash
console.log(_.gte(3, 1))
// output: true
// Native
console.log(3 >= 1);
// output: true
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_.isEmpty
Checks if value is an empty object or collection.
Note that the Native version does not support evaluating a Set or a Map
// Lodash
console.log(_.isEmpty(null))
// output: true
console.log(_.isEmpty(''))
// output: true
console.log(_.isEmpty({}))
// output: true
console.log(_.isEmpty([]))
// output: true
console.log(_.isEmpty({a: '1'}))
// output: false
// Native
const isEmpty = obj => [Object, Array].includes((obj || {}).constructor) && !Object.entries((obj || {})).length;
console.log(isEmpty(null))
// output: true
console.log(isEmpty(''))
// output: true
console.log(isEmpty({}))
// output: true
console.log(isEmpty([]))
// output: true
console.log(isEmpty({a: '1'}))
// output: false
Array.prototype.includes()
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47.0 |
14.0 |
43.0 |
34.0 |
9.0 |
_.isFinite
Checks if value is a finite primitive number.
// Lodash
console.log(_.isFinite('3'))
// output: false
console.log(_.isFinite(3))
// output: true
// Native
console.log(Number.isFinite('3'))
// output: false
console.log(Number.isFinite(3))
// output: true
Number.isFinite()
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19.0 |
16.0 |
15.0 |
9.0 |
_.isInteger
Checks if value is an integer.
// Lodash
console.log(_.isInteger(3))
// output: true
console.log(_.isInteger('3'))
// output: false
// Native
console.log(Number.isInteger(3))
// output: true
console.log(Number.isInteger('3'))
// output: false
Number.isInteger()
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12 |
16.0 |
_.isNaN
Checks if a value is NaN.
// Underscore/Lodash
console.log(_.isNaN(NaN))
// output: true
// Native
console.log(isNaN(NaN))
// output: true
// ES6
console.log(Number.isNaN(NaN))
// output: true
MDN:
In comparison to the global
isNaN()
function,Number.isNaN()
doesn't suffer the problem of forcefully converting the parameter to a number. This means it is now safe to pass values that would normally convert toNaN
, but aren't actually the same value asNaN
. This also means that only values of the type number, that are alsoNaN
, return true. Number.isNaN()
Voice from the Lodash author:
Lodash's
_.isNaN
is equiv to ES6Number.isNaN
which is different than the globalisNaN
. --- jdalton
isNaN
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1.0 |
Number.isNaN
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25.0 |
15.0 |
9.0 |
_.isNil
Not in Underscore.js
Checks if value is null or undefined.
// Lodash
console.log(_.isNil(null))
// output: true
console.log(_.isNil(NaN))
// output: false
console.log(_.isNil(undefined))
// output: true
// Native
console.log(null == null);
// output: true
console.log(NaN == null);
// output: false
console.log(undefined == null)
// output: true
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_.isNull
Checks if value is null.
// Underscore/Lodash
console.log(_.isNull(null))
// output: true
console.log(_.isNull(void 0))
// output: false
// Native
console.log(null === null);
// output: true
console.log(void 0 === null);
// output: false
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_.isUndefined
Checks if value is undefined.
// Underscore/Lodash
console.log(_.isUndefined(a))
// output: true
// Native
console.log(typeof a === 'undefined');
// output: true
console.log(a === undefined);
// output: true
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1 |
Object
_.assign
The method is used to copy the values of all enumerable own properties from one or more source objects to a target object.
// Underscore: _.extendOwn
// Lodash
function Foo() {
this.c = 3;
}
function Bar() {
this.e = 5;
}
Foo.prototype.d = 4;
Bar.prototype.f = 6;
var result = _.assign(new Foo, new Bar);
console.log(result);
// output: { 'c': 3, 'e': 5 }
// Native
function Foo() {
this.c = 3;
}
function Bar() {
this.e = 5;
}
Foo.prototype.d = 4;
Bar.prototype.f = 6;
var result = Object.assign({}, new Foo, new Bar);
console.log(result);
// output: { 'c': 3, 'e': 5 }
Object.assign()
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45.0 |
34.0 |
32.0 |
9.0 |
_.defaults
The method is used to apply new values over an object with default values for keys.
// Underscore: _.defaults
// Lodash
const newValues = {a: 3};
const defaultValues = {a: 1, b: 2}
const appliedValues = _.defaults(newValues, defaultValues);
console.log(appliedValues)
// output { a: 3, b: 2 }
// Native
const newValues = {a: 3};
const defaultValues = {a: 1, b: 2}
const appliedValues = Object.assign({}, defaultValues, newValues);
// output { a: 3, b: 2 }
Object.assign()
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45.0 |
34.0 |
32.0 |
9.0 |
_.extend
The method is used to copy the values of all enumerable own and inherited properties from one or more source objects to a target object.
// Underscore
// Lodash: _.assignIn
function Foo() {
this.c = 3;
}
function Bar() {
this.e = 5;
}
Foo.prototype.d = 4;
Bar.prototype.f = 6;
var result = _.extend({}, new Foo, new Bar);
console.log(result);
// output: { 'c': 3, 'd': 4, 'e': 5, 'f': 6 }
// Native
function Foo() {
this.c = 3;
}
function Bar() {
this.e = 5;
}
Foo.prototype.d = 4;
Bar.prototype.f = 6;
var result = Object.assign({}, new Foo, Foo.prototype, new Bar, Bar.prototype);
console.log(result);
// output: { 'c': 3, 'd': 4, 'e': 5, 'f': 6 }
//Or using a function
const extend = (target, ...sources) => {
const length = sources.length;
if (length < 1 || target == null) return target;
for (let i = 0; i < length; i++) {
const source = sources[i];
for (const key in source) {
target[key] = source[key];
}
}
return target;
};
console.log(extend({}, new Foo, new Bar));
// output: { 'c': 3, 'd': 4, 'e': 5, 'f': 6 }
Object.assign()
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45.0 |
34.0 |
32.0 |
9.0 |
_.has
Checks if key
is a direct property of object
. Key may be a path of a value separated by .
// Lodash
var object = { a: 1, b: 'settings', c: { d: 'test' } };
var hasA = _.has(object, 'a');
var hasCWhichHasD = _.has(object, 'c.d')
console.log(hasA);
// output: true
console.log(hasCWhichHasD);
// output: true
// Native
const has = function (obj, key) {
var keyParts = key.split('.');
return !!obj && (
keyParts.length > 1
? has(obj[key.split('.')[0]], keyParts.slice(1).join('.'))
: hasOwnProperty.call(obj, key)
);
};
var object = { a: 1, b: 'settings' };
var result = has(object, 'a');
// output: true
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12 |
5.5 |
5 |
3 |
_.get
Gets the value at path of object. Note: If provided path does not exist inside the object js will generate error.
// Lodash
var object = { a: [{ b: { c: 3 } }] };
var result = _.get(object, 'a[0].b.c', 1);
console.log(result);
// output: 3
// Native (ES6 - IE not supported)
var object = { a: [{ b: { c: 3 } }] };
var { a: [{ b: { c: result = 1 } = {} } = {}] = [] } = object;
console.log(result);
// output: 3
// Native (ES11)
var object = { a: [{ b: { c: 3 } }] };
var result = object?.a?.[0]?.b?.c ?? 1;
console.log(result);
// output: 3
// Native
const get = (obj, path, defaultValue = undefined) => {
const travel = regexp =>
String.prototype.split
.call(path, regexp)
.filter(Boolean)
.reduce((res, key) => (res !== null && res !== undefined ? res[key] : res), obj);
const result = travel(/[,[\]]+?/) || travel(/[,[\].]+?/);
return result === undefined || result === obj ? defaultValue : result;
};
var object = { a: [{ b: { c: 3 } }] };
var result = get(object, 'a[0].b.c', 1);
// output: 3
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49.0 |
14.0 |
41.0 |
41.0 |
8.0 |
?.
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80.0 |
80.0 |
74.0 |
67.0 |
13.1 |
??
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80.0 |
80.0 |
72.0 |
13.1 |
_.keys
Retrieves all the names of the object's own enumerable properties.
// Underscore/Lodash
var result = _.keys({one: 1, two: 2, three: 3})
console.log(result)
// output: ["one", "two", "three"]
// Native
var result2 = Object.keys({one: 1, two: 2, three: 3})
console.log(result2)
// output: ["one", "two", "three"]
Object.keys()
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5.0 |
4.0 |
9.0 |
12.0 |
5.0 |
_.omit
Returns a copy of the object, filtered to omit the keys specified.
var object = { 'a': 1, 'b': '2', 'c': 3 };
// Underscore/Lodash
var result = _.omit(object, ['a', 'c']);
console.log(result)
// output: { 'b': '2' }
// Native
var { a, c, ...result2 } = object;
console.log(result2)
// output: { 'b': '2' }
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60.0 |
55.0 |
37.0 |
_.pick
Creates an object composed of the object properties predicate returns truthy for.
var object = { 'a': 1, 'b': '2', 'c': 3 };
// Underscore/Lodash
var result = _.pick(object, ['a', 'c']);
console.log(result)
// output: {a: 1, c: 3}
// Native
const { a, c } = object;
const result = { a, c};
console.log(result);
// output: {a: 1, c: 3}
// for an array of this object --> array.map(({a, c}) => ({a, c}));
// Native
function pick(object, keys) {
return keys.reduce((obj, key) => {
if (object && object.hasOwnProperty(key)) {
obj[key] = object[key];
}
return obj;
}, {});
}
var result = pick(object, ['a', 'c']);
console.log(result)
// output: {a: 1, c: 3}
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