History of Array.prototype.includes() Revision history for: English (US) Aug 31, 2016, 10:43:53 PM rmcvey Technical review completed. Previous Aug 31, 2016, 10:36:25 PM tresf Support added to Edge per https://developer.microsoft.com/en-us/microsoft-edge/platform/status/arrayprototypeincludeses2016/?q=includes Previous Jul 29, 2016, 1:46:25 AM BendingBender added throwing TypeErrors when method is called on null or undefined, according to spec Previous Jul 14, 2016, 3:16:10 AM fscholz Revert to revision of 2016-07-08 05:34:41 by fscholz: "See reference implementation for correct polyfill. https://github.com/tc39/Array.prototype.includes/blob/master/reference-implementation/index.js" Previous Jul 13, 2016, 3:57:00 PM MelleB Simplify polyfill method, also accepts fromIndex parameter in the new version. Previous Jul 8, 2016, 5:34:41 AM fscholz Previous Jun 27, 2016, 9:29:44 AM jlowcs Fixed issue with polyfill which made it work only with numbers. Went back to the Revision 1062202 way of testing NaN. Previous Jun 20, 2016, 11:38:52 PM tjcrowder Correct the polyfill, which didn't use the SameValueZero algorithm. Compare old (https://jsfiddle.net/gwdjcdLy/) to updated (https://jsfiddle.net/c5fwLtqy/) Previous May 30, 2016, 10:05:27 AM 1337micro Previous May 19, 2016, 2:39:49 AM mazkasa i found this article has wrong part. According to the spec, when the optional second arg fromIndex is negative, then the value is used as the offset from the end of the array to compute fromIndex. and the search order is asc.