angular/angular.js — pull request #2535 by robinboehm (2013-04-28 18:10:44+00:00)
Title: feat(ngClass): improve performance through bitwise operations

minimal change to improve the performance.

Change modulo % 2 operations to bitwise & 1

Read at Nicholas C. Zakas book "High Performance JavaScript"(ISBN: 978-0-596-80279-0)
Use the Fast Parts --> Bitwise Operators --> Page 156++

Proven at http://jsperf.com/modulo-vs-bitwise/11