lodash

Lo-Dash ^v0.8.0

A drop-in replacement^* for Underscore.js, from the devs behind jsPerf.com, delivering performance, bug fixes, and additional features.

Lo-Dash’s performance is gained by avoiding slower native methods, instead opting for simplified non-ES5 compliant methods optimized for common usage, and by leveraging function compilation to reduce the number of overall function calls.

Download

• Development build
• Production build
• Underscore build tailored for projects already using Underscore
• CDN copies of ≤ v0.8.0 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

Features

• AMD loader support (RequireJS, curl.js, etc.)
• _.clone supports “deep” cloning
• _.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
• _.lateBind for late binding
• _.merge for a “deep” _.extend
• _.partial for partial application without this binding
• _.pick and _.omit accept callback and thisArg arguments
• _.template utilizes sourceURLs for easier debugging
• _.contains, _.size, _.toArray, and more… accept strings

Support

Lo-Dash has been tested in at least Chrome 5-22, Firefox 1-15, IE 6-10, Opera 9.25-12, Safari 3-6, Node.js 0.4.8-0.8.11, Narwhal 0.3.2, RingoJS 0.8, and Rhino 1.7RC5.

Custom builds

Custom builds make it easy to create lightweight versions of Lo-Dash containing only the methods you need. To top it off, we handle all method dependency and alias mapping for you.

• Backbone builds, with only methods required by Backbone, may be created using the backbone modifier argument.

lodash backbone

• CSP builds, supporting default Content Security Policy restrictions, may be created using the csp modifier argument.

lodash csp

• Legacy builds, tailored for older browsers without ES5 support, may be created using the legacy modifier argument.

lodash legacy

• Mobile builds, with IE < 9 bug fixes and method compilation removed, may be created using the mobile modifier argument.

lodash mobile

• Strict builds, with _.bindAll, _.defaults, and _.extend in strict mode, may be created using the strict modifier argument.

lodash strict

• Underscore builds, tailored for projects already using Underscore, may be created using the underscore modifier argument.

lodash underscore

Custom builds may be created using the following commands:

• Use the category argument to pass comma separated categories of methods to include in the build.
  Valid categories (case-insensitive) are “arrays”, “chaining”, “collections”, “functions”, “objects”, and “utilities”.

lodash category=collections,functions
lodash category="collections, functions"

• Use the exports argument to pass comma separated names of ways to export the LoDash function.
  Valid exports are “amd”, “commonjs”, “global”, “node”, and “none”.

lodash exports=amd,commonjs,node
lodash exports="amd, commonjs, node"

• Use the iife argument to specify code to replace the immediately-invoked function expression that wraps Lo-Dash.

lodash iife="!function(window,undefined){%output%}(this)"

• Use the include argument to pass comma separated method/category names to include in the build.

lodash include=each,filter,map
lodash include="each, filter, map"

• Use the minus argument to pass comma separated method/category names to remove from those included in the build.

lodash underscore minus=result,shuffle
lodash underscore minus="result, shuffle"

• Use the plus argument to pass comma separated method/category names to add to those included in the build.

lodash backbone plus=random,template
lodash backbone plus="random, template"

• Use the template argument to pass the file path pattern used to match template files to precompile

lodash template="./*.jst"

• Use the settings argument to pass the template settings used when precompiling templates

lodash settings="{interpolate:/\\{\\{([\\s\\S]+?)\\}\\}/g}"

All arguments, except legacy with csp or mobile, may be combined.
Unless specified by -o or --output, all files created are saved to the current working directory.

The following options are also supported:

• -c, --stdout     Write output to standard output
• -d, --debug       Write only the debug output
• -h, --help         Display help information
• -m, --minify     Write only the minified output
• -o, --output     Write output to a given path/filename
• -s, --silent     Skip status updates normally logged to the console
• -V, --version   Output current version of Lo-Dash

The lodash command-line utility is available when Lo-Dash is installed as a global package (i.e. npm install -g lodash).

Installation and usage

In browsers:

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

Using npm:

npm install lodash
npm install -g lodash

In Node.js and RingoJS v0.8.0+:

var _ = require('lodash');

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

• Add AMD loader support [#431, test]
• Allow iteration of objects with a length property [#799, test]
• Ensure “Collections” methods allow string collection arguments [#247, #276, #561, test]
• Fix cross-browser object iteration bugs [#60, #376, test]
• Methods should work on pages with incorrectly shimmed native methods [#7, #742, test]
• _.clone should allow deep cloning [#595, test]
• _.contains should work with strings [#667, test]
• _.extend should recursively extend objects [#379, #718, test]
• _.forEach should be chainable [#142, test]
• _.forEach should allow exiting iteration early [#211, 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]
• _.throttle should work when called in a loop [#502, test]

Optimized methods ⁽⁵⁰⁺⁾

• _.bind
• _.bindAll
• _.compact
• _.contains, _.include
• _.defaults
• _.difference
• _.each
• _.every, _.all
• _.extend
• _.filter, _.select
• _.find, _.detect
• _.flatten
• _.forEach, _.each
• _.functions, _.methods
• _.groupBy
• _.indexOf
• _.intersection
• _.invert
• _.invoke
• _.isArguments
• _.isDate
• _.isFinite
• _.isFunction
• _.isObject
• _.isNumber
• _.isRegExp
• _.isString
• _.keys
• _.lastIndexOf
• _.map, _.collect
• _.max
• _.memoize
• _.min
• _.mixin
• _.omit
• _.pairs
• _.pick
• _.pluck
• _.reduce, _.foldl, _.inject
• _.reject
• _.result
• _.shuffle
• _.some, _.any
• _.sortBy
• _.sortedIndex
• _.template
• _.throttle
• _.toArray
• _.union
• _.uniq, _.unique
• _.values
• _.where
• _.without
• _.wrap
• _.zip
• plus all _(…) method wrappers

Release Notes

^v0.8.0

Compatibility Warnings

• Made _.random return 0 or 1 when no arguments are passed
• Moved late bind functionality from _.bind to _.lateBind
• Removed first argument falsey checks from methods
• Removed support for custom clone, isEqual, toArray methods from
  _.clone, _.isEqual, and _.toArray

Changes

• Added -d/--debug, -m/--minify, minus, plus, settings, and template build options
• Added _.isPlainObject and _.lateBind
• Allowed _.sortedIndex to accept a property name as the callback argument
• Ensured methods accept a thisArg of null
• Fixed the iife build option to accept more values
• Made _.times return an array of callback results
• Simplified _.max, _.min, and _.reduceRight

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

• Kit Cambridge
• Mathias Bynens