lodash

What is lodash?

Lodash is a JavaScript library that provides utility functions for common programming tasks using a functional programming paradigm. It includes functions for manipulating and traversing arrays, objects, and strings, as well as utilities for functions, language, math, number, object, sequence, and utility methods.

What are lodash's main functionalities?

Array Manipulation

Lodash provides a rich set of array manipulation functions such as map, filter, find, and sort. The code sample demonstrates sorting an array in ascending order using a custom comparator.

[3, 2, 1].sort(_.compareWith(function(a, b) { return a - b; }))

Object Manipulation

Lodash allows for easy manipulation and traversal of objects. The code sample shows how to assign properties from source objects to a destination object.

_.assign({ 'a': 1 }, { 'b': 2 }, { 'c': 3 })

String Manipulation

Lodash includes functions to manipulate strings, such as converting to different cases, trimming, padding, etc. The code sample demonstrates converting a string to kebab-case.

_.kebabCase('Foo Bar')

Function Utilities

Lodash provides function utilities like debounce and throttle to control function invocation. The code sample shows a debounced function that will only be invoked after 250 milliseconds have passed without it being called again.

_.debounce(function() { console.log('Debounced'); }, 250)

Language Utilities

Lodash includes utilities for deep cloning, merging, and comparing objects. The code sample demonstrates deep cloning an object to ensure nested objects are cloned as well.

_.cloneDeep({ 'a': 1, 'b': { 'c': 2 } })

Other packages similar to lodash

underscore

Underscore is a utility library with similar functionality to Lodash, offering a range of functions for manipulating arrays, objects, and functions. It is generally considered to be the predecessor to Lodash, which provides a superset of Underscore's features with additional performance optimizations.

ramda

Ramda is a functional programming library that emphasizes a more functional and composable approach compared to Lodash. It provides similar utilities but focuses on immutability and side-effect free functions, which can lead to a different programming style.

immutable

Immutable.js offers a different take on data manipulation by providing persistent immutable data structures. Unlike Lodash, which works with standard JavaScript objects and arrays, Immutable.js uses its own data structures, which can lead to better performance and easier reasoning about state changes in certain applications.

README

lodash v4.6.0

The lodash library exported as Node.js modules.

Installation

Using npm:

$ {sudo -H} npm i -g npm
$ npm i --save lodash

In Node.js:

// Load the full build.
var _ = require('lodash');
// Load the core build.
var _ = require('lodash/core');
// Load the fp build for immutable auto-curried iteratee-first data-last methods.
var _ = require('lodash/fp');

// Load a method category.
var array = require('lodash/array');
var object = require('lodash/fp/object');

// Load a single method for smaller builds with browserify/rollup/webpack.
var chunk = require('lodash/chunk');
var extend = require('lodash/fp/extend');

See the package source for more details.

Note:
Don’t assign values to the special variable _ when in the REPL.
Install n_ for a REPL that includes lodash by default.

Support

Tested in Chrome 47-48, Firefox 43-44, IE 9-11, Edge 13, Safari 8-9, Node.js 0.10, 0.12, 4, & 5, & PhantomJS 1.9.8.
Automated browser & CI test runs are available.