JavaScript includes and indexOf not working in IE8

Question

Hi Everyone, I am working with one of the projects to make it compatible with IE8. I got this issue as I have shown below, will you please give me any alternate way or suggestion to use these functions in Javascript? SCRIPT438: Object doesn't support property or method 'includes' SCRIPT436: Object doesn't support property or method ' indexOf ' I tried this function includes(container, value) { var returnValue = false ; var pos = container.indexOf(value); if (pos >= 0) { returnValue = true ; } return returnValue; } includes([1,2,3],2) //=> true includes([1,2,3], 'a' ) //=> false Also tryed if (!String.prototype.includes) { //To check browser supports or not String.prototype.includes = function (str) { //If not supported, then define the method return this .indexOf(str) !== -1; } } but not work well for IE8. Will anyone please help me.

Nikunj Satasiya · Answer

Hi Everyone, I got the solution, I would like to share it with the community to resolve such kinds of issues very quickly. I just put this code in my common script file and it works now well in IE8. Please let me know if you have any optimized way to fix this issue. Array.prototype.includes = null ; Array.prototype.indexOf = null ; if (!Array.prototype.includes) { //or use Object.defineProperty Array.prototype.includes = function (search) { return !!~ this .indexOf(search); } } if (!Array.prototype.indexOf) { Array.prototype.indexOf = ( function (Object, max, min) { "use strict" ; return function indexOf(member, fromIndex) { if ( this === null || this === undefined) throw TypeError( "Array.prototype.indexOf called on null or undefined" ); var that = Object( this ), Len = that.length >>> 0, i = min(fromIndex | 0, Len); if (i else if (i >= Len) return -1; if (member === void 0) { for (; i !== Len; ++i) if (that[i] === void 0 && i in that) return i; // undefined } else if (member !== member) { for (; i !== Len; ++i) if (that[i] !== that[i]) return i; // NaN } else for (; i !== Len; ++i) if (that[i] === member) return i; // all else return -1; // if the value was not found, then return -1 }; })(Object, Math.max, Math.min); }