A drop-in replacement for Underscore.js, from the devs behind[jsPerf.com](http://jsperf.com), that delivers[performance improvements](http://lodash.com/benchmarks),[bug fixes](https://github.com/bestiejs/lodash#closed-underscorejs-issues), and[additional features](https://github.com/bestiejs/lodash#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.

*[Development source](https://raw.github.com/bestiejs/lodash/v0.3.0/lodash.js)

*[Production source](https://raw.github.com/bestiejs/lodash/v0.3.0/lodash.min.js)

*[Development source](https://raw.github.com/bestiejs/lodash/v0.3.1/lodash.js)

*[Production source](https://raw.github.com/bestiejs/lodash/v0.3.1/lodash.min.js)

* For optimal performance,[create a custom build](https://github.com/bestiejs/lodash#custom-builds) with only the features you need

* AMD loader support (RequireJS,curl.js, etc.)

* AMD loader support ([RequireJS](http://requirejs.org/),[curl.js](https://github.com/cujojs/curl), etc.)

*[_.bind](http://lodash.com/docs#bind) supports*"lazy"* binding

*[_.debounce](http://lodash.com/docs#debounce)’ed functions match[_.throttle](http://lodash.com/docs#throttle)’ed functions’ return value behavior

*[_.forEach](http://lodash.com/docs#forEach) is chainable

* Allow iteration of objects with a`length` property[[#148](https://github.com/documentcloud/underscore/issues/148),[#154](https://github.com/documentcloud/underscore/issues/154),[#252](https://github.com/documentcloud/underscore/issues/252),[#448](https://github.com/documentcloud/underscore/issues/448),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L266-272)]

* Ensure array-like objects with invalid`length` properties are treated like regular objects[[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L237-243),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L533-542),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L661-664)]

* Ensure`_(...)` returns passed wrapper instances[[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L106-109)]

* Ensure`_.groupBy` adds values to own, not inherited, properties[[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L317-324)]

* Ensure`_.sortedIndex` supports arrays with high`length` values[[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L586-595)]

* Ensure`_.throttle` works when called in tight loops[[#502](https://github.com/documentcloud/underscore/issues/502),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L629-639)]

* Fix Firefox, IE, Opera, and Safari object iteration bugs[[#376](https://github.com/documentcloud/underscore/issues/376),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L175-187),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L277-302),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L379-390),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L398-400),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L418-438),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L554-556)]

* Allow iteration of objects with a`length` property[[#148](https://github.com/documentcloud/underscore/issues/148),[#154](https://github.com/documentcloud/underscore/issues/154),[#252](https://github.com/documentcloud/underscore/issues/252),[#448](https://github.com/documentcloud/underscore/issues/448),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L266-272)]

* Ensure "Arrays" category methods allow falsey`array` arguments[[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L714-748)]

* Ensure array-like objects with invalid`length` properties are treated like regular objects[[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L237-243),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L533-542),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L661-664)]

* Ensure`_(...)` returns passed wrapper instances[[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L106-109)]

* Ensure`_.groupBy` adds values to own, not inherited, properties[[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L317-324)]

* Ensure`_.sortedIndex` supports arrays with high`length` values[[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L586-595)]

* Ensure`_.throttle` works when called in tight loops[[#502](https://github.com/documentcloud/underscore/issues/502),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L629-639)]

* Fix Firefox, IE, Opera, and Safari object iteration bugs[[#376](https://github.com/documentcloud/underscore/issues/376),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L175-187),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L277-302),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L379-390),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L398-400),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L418-438),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L554-556)]

* Handle arrays with`undefined` values correctly in IE < 9[[#601](https://github.com/documentcloud/underscore/issues/601)]

* Methods should work on pages with incorrectly shimmed native methods[[#7](https://github.com/documentcloud/underscore/issues/7),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L88-94)]

* Register as AMD module, but still export to global[[#431](https://github.com/documentcloud/underscore/pull/431),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L72-86)]

*`_.forEach` should be chainable[[#142](https://github.com/documentcloud/underscore/issues/142),[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L232-235)]

*`_isNaN(new Number(NaN))` should return`true`[[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L408-410)]

*`_.reduceRight` should pass correct callback arguments when iterating objects[[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L521-531)]

*`_.size` should return the`length` of string values[[test](https://github.com/bestiejs/lodash/blob/c07e1567a7a12cff2c5ee6cda81306c8bcf126f0/test/test.js#L550-552)]

* Methods should work on pages with incorrectly shimmed native methods[[#7](https://github.com/documentcloud/underscore/issues/7),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L88-94)]

* Register as AMD module, but still export to global[[#431](https://github.com/documentcloud/underscore/pull/431),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L72-86)]

*`_.forEach` should be chainable[[#142](https://github.com/documentcloud/underscore/issues/142),[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L232-235)]

*`_isNaN(new Number(NaN))` should return`true`[[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L408-410)]

*`_.reduceRight` should pass correct callback arguments when iterating objects[[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L521-531)]

*`_.size` should return the`length` of string values[[test](https://github.com/bestiejs/lodash/blob/801e8a5b3a963157fceaad15075690f59c22de9c/test/test.js#L550-552)]

* Added`backbone` build option

* Ensured "Arrays" category methods allow falsey`array` arguments

* Removed`_.isArguments` fallback from the`mobile` build

* Simplified`_.pluck`,`_.values` and`_(...)` method wrappers

* Added`category` build option

$markdown =docdown(array(

'path' =>'../' .$file,

'title' =>'Lo-Dash ^v0.3.0',

'url' =>'https://github.com/bestiejs/lodash/blob/v0.3.0/lodash.js'

'title' =>'Lo-Dash ^v0.3.1',

'url' =>'https://github.com/bestiejs/lodash/blob/v0.3.1/lodash.js'

));

{

"name":"lodash",

"version":"0.3.0",

"version":"0.3.1",

"description":"A drop-in replacement for Underscore.js that delivers performance improvements, bug fixes, and additional features.",

"homepage":"http://lodash.com",

"main":"lodash",