jashkenas/underscore — pull request #1285 by ameyms (2013-09-08 17:17:05+00:00)
Title: Do not use native ES5 methods by default since for loops are faster

`for` loops are way faster than native ES5 array traversal methods methods due to JIT optimizations.
Hence use `for` loops by default and provide a method to turn on/off usage of these ES5 methods

JsPerf:
http://jsperf.com/array-filter-vs-for-loop
http://jsperf.com/jqeach-vs-for-vs-foreach