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 of the functions, Lodash provides you more options than native built-ins. This list is not a 1:1 comparison.
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
I guess not, but I want it.
—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.
'plugins': ['you-dont-need-lodash-underscore'],
'rules': {
'you-dont-need-lodash-underscore/all': 1,
...
}
Quick links
Array
- _.concat
- _.fill
- _.find
- _.findIndex
- _.indexOf
- _.join
- _.lastIndexOf
- _.reverse
Collection*
:heavy_exclamation_mark:Important: Note that the native equivalents are array methods,
and will not work with objects. If this functionality is needed,
then Lodash/Underscore is the better option.
- _.each
- _.every
- _.filter
- _.includes
- _.map
- _.reduce
- _.reduceRight
- _.size
- _.some
Function
- _.after
Lang
- _.isNaN
Object
- _.assign
- _.keys
String
- _.repeat
- _.toLower
- _.toUpper
- _.trim
Array
_.concat
Creates a new array concatenating array with any additional arrays and/or values.
var array = [1]
var other = _.concat(array, 2, [3], [[4]])
console.log(other)
var array = [1]
var other = array.concat(2, [3], [[4]])
console.log(other)
Browser Support
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_.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.
var array = [1, 2, 3]
_.fill(array, 'a')
console.log(array)
_.fill(Array(3), 2)
_.fill([4, 6, 8, 10], '*', 1, 3)
var array = [1, 2, 3]
array.fill('a')
console.log(array)
Array(3).fill(2)
[4, 6, 8, 10].fill('*', 1, 3)
Browser Support
| | | | |
---|
45.0 | 31.0 ✔ | Not supported | Not supported | 7.1 |
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_.find
Returns a value in the array, if an element in the array satisfies the provided testing function. Otherwise undefined is returned.
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; })
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; })
Browser Support
| | | | |
---|
45.0 | 25.0 ✔ | Not supported | Not supported | 7.1 |
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_.findIndex
Returns an index in the array, if an element in the array satisfies the provided testing function. Otherwise -1 is returned.
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)
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)
Browser Support
| | | | |
---|
45.0 | 25.0 ✔ | Not supported | Not supported | 7.1 |
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_.indexOf
Returns the first index at which a given element can be found in the array, or -1 if it is not present.
var array = [2, 9, 9]
var result = _.indexOf(array, 2)
console.log(result)
var array = [2, 9, 9]
var result = array.indexOf(2)
console.log(result)
Browser Support
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_.join
:heavy_exclamation_mark:Lodash only
Joins a list of elements in an array with a given separator.
var result = _.join(['one', 'two', 'three'], '--')
console.log(result)
var result = ['one', 'two', 'three'].join('--')
console.log(result)
Browser Support
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_.lastIndexOf
Returns the index of the last occurrence of value in the array, or -1 if value is not present.
var array = [2, 9, 9, 4, 3, 6]
var result = _.lastIndexOf(array, 9)
console.log(result)
var array = [2, 9, 9, 4, 3, 6]
var result = array.lastIndexOf(9)
console.log(result)
Browser Support
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_.reverse
:heavy_exclamation_mark:Lodash only
Reverses array so that the first element becomes the last, the second element becomes the second to last, and so on.
var array = [1, 2, 3]
console.log(_.reverse(array))
var array = [1, 2, 3]
console.log(array.reverse())
Voice from the Lodash author:
Lodash's _.reverse
just calls Array#reverse
and enables composition like _.map(arrays, _.reverse).
It's exposed on _ because previously, like Underscore
, it was only exposed in the chaining syntax.
--- jdalton
Browser Support
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Collection*
:heavy_exclamation_mark:Important: Note that the native equivalents are array methods,
and will not work with objects. If this functionality is needed,
then Lodash/Underscore is the better option.
_.each
Iterates over a list of elements, yielding each in turn to an iteratee function.
_.each([1, 2, 3], function (value, index) {
console.log(value)
})
[1, 2, 3].forEach(function (value, index) {
console.log(value)
})
Browser Support
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_.every
Tests whether all elements in the array pass the test implemented by the provided function.
function isLargerThanTen (element, index, array) {
return element >= 10
}
var array = [10, 20, 30]
var result = _.every(array, isLargerThanTen)
console.log(result)
function isLargerThanTen (element, index, array) {
return element >= 10
}
var array = [10, 20, 30]
var result = array.every(isLargerThanTen)
console.log(result)
Browser Support
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_.filter
Creates a new array with all elements that pass the test implemented by the provided function.
function isBigEnough (value) {
return value >= 10
}
var array = [12, 5, 8, 130, 44]
var filtered = _.filter(array, isBigEnough)
console.log(filtered)
function isBigEnough (value) {
return value >= 10
}
var array = [12, 5, 8, 130, 44]
var filtered = array.filter(isBigEnough)
console.log(filtered)
Browser Support
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_.includes
Checks if value is in collection.
var array = [1, 2, 3]
_.includes(array, 1)
var array = [1, 2, 3]
array.includes(1)
Browser Support
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_.map
Translate all items in an array or object to new array of items.
var array1 = [1, 2, 3]
var array2 = _.map(array1, function (value, index) {
return value * 2
})
console.log(array2)
var array1 = [1, 2, 3]
var array2 = array1.map(function (value, index) {
return value * 2
})
console.log(array2)
Browser Support
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_.reduce
Applies a function against an accumulator and each value of the array (from left-to-right) to reduce it to a single value.
var array = [0, 1, 2, 3, 4]
var result = _.reduce(array, function (previousValue, currentValue, currentIndex, array) {
return previousValue + currentValue
})
console.log(result)
var array = [0, 1, 2, 3, 4]
var result = array.reduce(function (previousValue, currentValue, currentIndex, array) {
return previousValue + currentValue
})
console.log(result)
Browser Support
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_.reduceRight
This method is like _.reduce except that it iterates over elements of collection from right to left.
var array = [0, 1, 2, 3, 4]
var result = _.reduceRight(array, function (previousValue, currentValue, currentIndex, array) {
return previousValue - currentValue
})
console.log(result)
var array = [0, 1, 2, 3, 4]
var result = array.reduceRight(function (previousValue, currentValue, currentIndex, array) {
return previousValue - currentValue
})
console.log(result)
Browser Support
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_.size
Return the number of values in the collection.
var result = _.size({one: 1, two: 2, three: 3})
console.log(result)
var result2 = Object.keys({one: 1, two: 2, three: 3}).length
console.log(result2)
Browser Support
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_.some
Tests whether some element in the array passes the test implemented by the provided function.
function isLargerThanTen (element, index, array) {
return element >= 10
}
var array = [10, 9, 8]
var result = _.some(array, isLargerThanTen)
console.log(result)
function isLargerThanTen (element, index, array) {
return element >= 10
}
var array = [10, 9, 8]
var result = array.some(isLargerThanTen)
console.log(result)
Browser Support
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Function
_.after
:heavy_exclamation_mark: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']
var renderNotes = _.after(notes.length, render)
notes.forEach(function (note) {
console.log(note)
renderNotes()
})
notes.forEach(function (note, index) {
console.log(note)
if (notes.length === (index + 1)) {
render()
}
})
Browser Support
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Lang
_.isNaN
Checks if value is NaN.
console.log(_.isNaN(NaN))
console.log(isNaN(NaN))
console.log(Number.isNaN(NaN))
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 to NaN
, but aren't actually the same value as NaN
. This also means that only values of the type number, that are also NaN
, return true. Number.isNaN()
Voice from the Lodash author:
Lodash's _.isNaN
is equiv to ES6 Number.isNaN
which is different than the global isNaN
.
--- jdalton
Browser Support for isNaN
Browser Support for Number.isNaN
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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.
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);
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);
Browser Support
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_.keys
Retrieve all the names of the object's own enumerable properties.
var result = _.keys({one: 1, two: 2, three: 3})
console.log(result)
var result2 = Object.keys({one: 1, two: 2, three: 3})
console.log(result2)
Browser Support
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String
_.repeat
:heavy_exclamation_mark:Lodash only
Repeats the given string n times.
var result = _.repeat('abc', 2)
var result = 'abc'.repeat(2)
console.log(result)
Browser Support
| | | | |
---|
41✔ | 24✔ | Not supported | Not supported | 9 |
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_.toLower
:heavy_exclamation_mark:Lodash only
Lowercase a given string.
var result = _.toLower('FOOBAR')
console.log(result)
var result = 'FOOBAR'.toLowerCase()
console.log(result)
Browser Support
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_.toUpper
:heavy_exclamation_mark:Lodash only
Uppercase a given string.
var result = _.toUpper('foobar')
console.log(result)
var result = 'foobar'.toUpperCase()
console.log(result)
Browser Support
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_.trim
:heavy_exclamation_mark:Lodash only
Removes leading and trailing whitespace characters from string.
var result = _.trim(' abc ')
console.log(result)
var result = ' abc '.trim()
console.log(result)
Browser Support
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Reference
Inspired by:
License
MIT