angular/angular.js — pull request #5457 by kseamon (2013-12-17 19:41:37+00:00)
Title: perf: use faster check for $$ prefix

perf: use faster check for $$ prefix

Use two calls to charAt instead of substr to detect a $$prefix in the shallowCopy functions.
This makes shallowCopy 25-50% faster (depending on which browser is used).
http://jsperf.com/angular-shallow-copy