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

Lo-Dash v0.10.0

A utility library delivering consistency, customization, performance, & extras.

Download

• Development build
• Production build
• Underscore build tailored for projects already using Underscore
• CDN copies of ≤ v0.10.0’s Production, Underscore, and Development builds are available on cdnjs thanks to CloudFlare
• For optimal file size, create a custom build with only the features you need

Dive in

We’ve got API docs, benchmarks, and unit tests.

Create your own benchmarks at jsPerf, or search for existing ones.

For a list of upcoming features, check out our roadmap.

Screencasts

For more information check out these screencasts over Lo-Dash:

• Introducing Lo-Dash
• Lo-Dash optimizations and custom builds
• Lo-Dash’s origin and why it’s a better utility belt
• Unit testing in Lo-Dash
• Lo-Dash’s approach to native method use
• CascadiaJS: Lo-Dash for a better utility belt

Features

• AMD loader support (RequireJS, curl.js, etc.)
• _.clone supports “deep” cloning
• _.contains accepts a fromIndex argument
• _.forEach is chainable and supports exiting iteration early
• _.forIn for iterating over an object’s own and inherited properties
• _.forOwn for iterating over an object’s own properties
• _.isPlainObject checks if values are created by the Object constructor
• _.bindKey for binding “lazy” defined methods
• _.merge for a “deep” _.extend
• _.partial for partial application without this binding
• _.pick and _.omit accepts callback and thisArg arguments
• _.template supports ES6 delimiters and utilizes sourceURLs for easier debugging
• _.contains, _.size, _.toArray, and more… accept strings

Support

Lo-Dash has been tested in at least Chrome 523, Firefox 116, IE 6-10, Opera 9.25-12, Safari 3-6, Node.js 0.4.8-0.8.14, Narwhal 0.3.2, RingoJS 0.8, and Rhino 1.7RC5.

Installation and usage

In browsers:

<script src="lodash.js"></script>

Using npm:

npm install lodash

npm install -g lodash
npm link lodash

To avoid potential issues, update npm before installing Lo-Dash:

npm install npm -g

In Node.js and RingoJS v0.8.0+:

var _ = require('lodash');

Note: If Lo-Dash is installed globally, run npm link lodash in your project’s root directory before requiring it.

In RingoJS v0.7.0-:

var _ = require('lodash')._;

In Rhino:

load('lodash.js');

In an AMD loader like RequireJS:

require({
  'paths': {
    'underscore': 'path/to/lodash'
  }
},
['underscore'], function(_) {
  console.log(_.VERSION);
});

Resolved Underscore.js issues

• Allow iteration of objects with a length property [#799, test]
• Fix cross-browser object iteration bugs [#60, #376, test]
• Methods should work on pages with incorrectly shimmed native methods [#7, #742, test]
• _.isEmpty should support jQuery/MooTools DOM query collections [#690, test]
• _.isObject should avoid V8 bug #2291 [#605, test]
• _.keys should work with arguments objects cross-browser [#396, test]
• _.range should coerce arguments to numbers [#634, #683, test]

Release Notes

^v0.10.0

Compatibility Warnings

• Aligned _.defaults and _.extend with ES6 Object.assign
• Renamed _.lateBind to _.bindKey

Changes

• Added the build commands used to custom build copyright/license headers
• Added _.assign
• Ensured the underscore build of _.find returns the first, not last, matched value
• Ensured _defaults, _.extends, and _.merge works with _.reduce
• Made Lo-Dash’s npm package installation work with more system configurations
• Made _.extend an alias of _.assign
• Optimized _.contains, _.defaults, _.extend, and _.filter
• Restricted _.where to iterate only own properties of the source object
• Updated backbone build Lo-Dash method dependencies

The full changelog is available here.

BestieJS

Lo-Dash is part of the BestieJS “Best in Class” module collection. This means we promote solid browser/environment support, ES5 precedents, unit testing, and plenty of documentation.

Author

John-David Dalton

Contributors

Blaine Bublitz	Kit Cambridge	Mathias Bynens