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.
- Development source
- Production source
- CDN copies of ≤ v0.4.1 are available on cdnjs thanks to CloudFlare
- For optimal performance, create a custom build with only the features you need
For a list of upcoming features, check out our roadmap.
For more information check out these screencasts over Lo-Dash:
- Introducing Lo-Dash
- Optimizations and custom builds
- Lo-Dash’s origin and why it’s a better utility belt
- AMD loader support (RequireJS, curl.js, etc.)
- _.bind supports "lazy" binding
- .debounce’ed functions match .throttle’ed functions’ return value behavior
- _.forEach is chainable
- _.forIn for iterating over an object’s own and inherited properties
- _.forOwn for iterating over an object’s own properties
- .groupBy, .sortedIndex, and _.uniq accept a
- .indexOf and .lastIndexOf accept a
- _.partial for more functional fun
- _.template utilizes sourceURLs for easier debugging
- .contains, .size, _.toArray, and more… accept strings
Lo-Dash has been tested in at least Chrome 5-20, Firefox 1.5-13, IE 6-9, Opera 9.25-12, Safari 3.0.4-5.1.7, Node.js 0.4.8-0.8.2, Narwhal 0.3.2, RingoJS 0.8, and Rhino 1.7RC3.
Custom builds make it easy to create lightweight versions of Lo-Dash containing only the methods you need. We handle all the method dependency and alias mapping for you.
- Backbone builds, containing all methods required by Backbone, may be created using the
- Legacy builds, tailored for older browsers without ES5 support, may be created using the
- Mobile builds, with IE < 9 bug fixes and method compilation removed, may be created using the
- Strict builds, with
_.defaultsin strict mode, may be created using the
Custom builds may be created in three ways:
- Use the
categoryargument to pass the categories of methods to include in the build.
Valid categories are "arrays", "chaining", "collections", "functions", "objects", and "utilities".
lodash category=collections,functionslodash category="collections, functions"
- Use the
excludeargument to pass the names of methods to exclude from the build.
lodash exclude=union,uniq,ziplodash exclude="union, uniq, zip"
- Use the
includeargument to pass the names of methods to include in the build.
lodash include=each,filter,maplodash include="each, filter, map"
All arguments, except
mobile, may be combined.
lodash backbone legacy category=utilities exclude=first,lastlodash backbone mobile strict category=functions include=pick,uniq
lodash command-line utility is available when Lo-Dash is installed as a global package (i.e.
npm install -g lodash).
Custom builds are saved to
Installation and usage
npm install lodashnpm install -g lodash
var _ = ;
var _ = _;
In an AMD loader like RequireJS:
Closed Underscore.js issues (20+)
- Allow iteration of objects with a
lengthproperty [#148, #154, #252, #448, #659, test]
- Ensure array-like objects with invalid
lengthproperties are treated like regular objects [test, test, test]
- Ensure "Arrays" methods allow falsey
- Ensure "Collections" methods allow string
collectionarguments [#247, #276, #561, test, test, test, test]
- Ensure templates compiled with errors are inspectable [#666, test]
- Fix cross-browser object iteration bugs [#376, test, test, test, test, test, test]
- Handle arrays with
undefinedvalues correctly in IE < 9 [#601]
- Methods should work on pages with incorrectly shimmed native methods [#7, test]
- Register as an AMD module, but still export to global [#431, test]
_(…)should return passed wrapper instances [test]
_.containsshould work with strings [#667, test]
_.escapeshould return an empty string when passed
_.forEachshould be chainable [#142, test]
_.groupByshould add values to own, not inherited, properties [test]
_isNaN(new Number(NaN))should return
_.reduceRightshould pass correct callback arguments when iterating objects [test]
_.sizeshould return the
lengthof string values [test]
_.sizeshouldn't error on falsey values [#650, test]
_.sizeshould work with
argumentsobjects cross-browser [#653, test]
_.sortedIndexshould support arrays with high
_.templateshould not augment the
_.throttleshould work when called in a loop [#502, test]
_.zipObjectshould accept less than two arguments [test]
Optimized methods (50+)
- plus all
_.defaultsavoid strict mode errors when attempting to augment read-only properties
- Optimized the iteration of large arrays in
- Fixed build bugs related to removing variables
- Optimized build process to detect and remove more unused variables
scriptsentries to package.json
- Added cross-browser support for passing strings to "Collections" methods
- Optimized compiled templates
- Optimized inlining the
- Optimized object iteration for "Collections" methods
- Optimized partially applied
- Made compiled templates more debuggable
_.sizework with falsey values and consistent cross-browser with
_.sortByback to the "Collections" category
The full changelog is available here.
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.