Lo-Dash v2.4.1

_.assign({ 'a': 1 }, { 'b': 2 }, { 'c': 3 });
// → { 'a': 1, 'b': 2, 'c': 3 }
_.map([1, 2, 3], function(n) { return n * 3; });
// → [3, 6, 9]

Documentation

• API Documentation
• DevDocs – a searchable interface for our documentation

Download

Review the build differences & pick the one that’s right for you.

• Modern build (minified)
  For new environments like Chrome, Firefox, IE ≥ 9, & Safari ≥ 5.1
• Compatibility build (minified)
  For new & old environments like IE ≤ 8 & PhantomJS
• Underscore build (minified)
  A drop-in replacement for Underscore v1.5.2

CDN copies are available on cdnjs & jsDelivr.
Create custom builds with only the features you need.
Love modules? We’ve got you covered with lodash-amd, lodash-node, & npm packages per method.

Dive in

Check out our unit tests, benchmarks, changelog, roadmap, as well as community created podcasts, posts, & videos.

Installation

In a browser:

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

In an AMD loader:

require(['lodash'], function(_) {/*…*/});

Using npm:

$ npm i --save lodash

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

In Node.js:

var _ = require('lodash');
// or as Underscore
var _ = require('lodash/dist/lodash.underscore');

Note:
Don’t assign values to the special variable “_” when in the REPL

Features not in Underscore

• ~100% code coverage
• Module bundles for AMD & Node.js as well as npm packages
• Follows semantic versioning for releases
• _(…) supports intuitive chaining
• _.at for cherry-picking values
• _.bindKey for binding “lazy” defined methods
• _.clone supports shallow cloning of Date & RegExp objects
• _.cloneDeep for deep cloning arrays & objects
• _.contains accepts a fromIndex
• _.create for easier object inheritance
• _.curry for creating curried functions
• _.debounce & _.throttle accept additional options for more control
• _.findIndex & _.findKey for finding indexes & keys
• _.forEach supports exiting early
• _.forIn for iterating own & inherited properties
• _.forOwn for iterating own properties
• _.isPlainObject for checking if values are created by Object
• _.mapValues for mapping values to an object
• _.merge for a deep _.extend
• _.parseInt for consistent behavior
• _.pull & _.remove for mutating arrays
• _.random supports returning floating-point numbers
• _.sortBy supports sorting by multiple properties
• _.runInContext for collisionless mixins & easier mocking
• _.support for flagging environment features
• _.template supports “imports” options & ES6 template delimiters
• _.transform as a powerful alternative to _.reduce for transforming objects
• _.where supports deep comparisons
• _.xor as a companion to _.difference, _.intersection, & _.union
• _.clone, _.isEqual, & more accept callbacks
• _.contains, _.toArray, & more accept strings
• _.findLast, _.findLastIndex, & more right-associative methods

Support

Tested in Chrome (19, 36-37), Firefox (3, 20, 31-32), IE 6-11, Opera 23-24, Safari 5-7, Node.js 0.8.26~0.10.32, PhantomJS 1.9.7, RingoJS 0.9, & Rhino 1.7RC5.

Automated browser test runs are available as well as CI runs for lodash, lodash-cli, lodash-amd, lodash-node, & grunt-lodash. Special thanks to Sauce Labs for providing automated browser testing.