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

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

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 v1.6.0

CDN copies are available on cdnjs & jsDelivr.
Create custom builds with only the features you need.
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Check out our unit tests, benchmarks, changelog, roadmap, as well as community created podcasts, posts, & videos.

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-underscore');

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

• ~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 collection values
• _.bindKey for binding "lazy" defined methods
• _.callback for extending callbacks in methods & mixins
• _.chunk for splitting an array into chunks of a given size
• _.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
• _.isError to check for error objects
• _.isPlainObject to check for objects created by Object
• _.keysIn & _.valuesIn for keys and values of own & inherited properties
• _.mapValues for mapping values to an object
• _.memoize exposes the cache of memoized functions
• _.merge for a deep _.extend
• _.negate to create negated predicate functions
• _.noop for function placeholders
• _.parseInt for consistent behavior
• _.pull, _.pullAt, & _.remove for mutating arrays
• _.random supports returning floating-point numbers
• _.runInContext for collisionless mixins & easier mocking
• _.slice for creating subsets of array-like values
• _.sortBy supports sorting by multiple properties
• _.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 object comparisons
• _.xor to complement _.difference, _.intersection, & _.union
• _.zip is capable of unzipping values
• _.bind, _.curry, _.partial, & more support argument placeholders
• _.capitalize, _.trim, & more string methods
• _.contains, _.toArray, & more accept strings
• _.dropWhile, _.takeWhile, & more to complement _.first, _.initial, _.last, & _.rest
• _.filter, _.map, & more support "_.pluck" & "_.where" shorthands
• _.findLast, _.findLastIndex, & more right-associative methods
• _.omit, _.pick, & more accept callbacks

Tested in Chrome (19, 35-36), Firefox (3, 20, 29-30), IE 6-11, Opera 21-22, Safari 5-7, Node.js 0.8.26~0.10.29, PhantomJS 1.9.2, 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.