raptor-polyfill/array/indexOf.js

Polyfills for various EcmaScript 5 and EcmaScript 6 methods distributed as CommonJS modules that can be require'd individually or as a whole.

// ES5 15.4.4.14
// http://es5.github.com/#x15.4.4.14
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/indexOf
if (!Array.prototype.indexOf) {
    var toObject = require('./_toObject');
    var toInteger = require('./_toInteger');
    
    Array.prototype.indexOf = function indexOf(sought /*, fromIndex */ ) {
        var self = toObject(this),
            length = self.length >>> 0;

        if (!length) {
            return -1;
        }

        var i = 0;
        if (arguments.length > 1) {
            i = toInteger(arguments[1]);
        }

        // handle negative indices
        i = i >= 0 ? i : Math.max(0, length + i);
        for (; i < length; i++) {
            if (i in self && self[i] === sought) {
                return i;
            }
        }
        return -1;
    };
}