lodash/README.md

Lo-Dash v3.0.0-pre

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

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 v1.6.0

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:

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

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

In Node.js:

// the default modern build
var _ = require('lodash');

// or the compat build
var _ = require('lodash-compat');

// or specific methods
var clone = require('lodash/lang/clone');
var keysIn = require('lodash-compat/object/keysIn');
var transform = require('lodash.transform');

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

Features not in Underscore

• ~100% code coverage
• Module bundles for AMD, ES6, & Node.js as well as npm packages
• Follows semantic versioning for releases
• Deferred chaining & lazy evaluation
• _(…) supports intuitive chaining
• _.ary & _.rearg to change function argument limits & order
• _.at for cherry-picking collection values
• _.attempt to execute functions which may error without a try-catch
• _.before to complement _.after
• _.bindKey for binding “lazy” defined methods
• _.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
• _.create for easier object inheritance
• _.curry & _.curryRight for creating curried functions
• _.debounce & _.throttle are cancelable & accept options for more control
• _.findIndex & _.findKey for finding indexes & keys
• _.flow to complement _.flowRight (a.k.a _.compose)
• _.forEach supports exiting early
• _.forIn for iterating all enumerable properties
• _.forOwn for iterating own properties
• _.includes accepts a fromIndex
• _.isError to check for error objects
• _.isNative to check for native functions
• _.isPlainObject to check for objects created by Object
• _.keysIn & _.valuesIn for getting keys & values of all enumerable properties
• _.mapValues for mapping values to an object
• _.merge for a deep _.extend
• _.parseInt for consistent cross-environment 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
• _.sortByAll for 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
• _.thru to pass values thru method chains
• _.where supports deep object comparisons
• _.xor to complement _.difference, _.intersection, & _.union
• _.bind, _.curry, _.partial, & more support customizable argument placeholders
• _.capitalize, _.trim, & more string methods
• _.clone, _.isEqual, & more accept callbacks
• _.dropWhile, _.takeWhile, & more to complement _.first, _.initial, _.last, & _.rest
• _.findLast, _.findLastIndex, & more right-associative methods
• _.includes, _.toArray, & more accept strings

Support

Tested in Chrome (19, 38-39), Firefox (3, 20, 33-34), IE 6-11, Opera 25-26, Safari 5-8, Node.js 0.8.26~0.10.35, PhantomJS 1.9.7, RingoJS 0.11, & 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.