https://repl.it/Cgt4/0 created by Sylvance

Cgt4-0.js

var contains = function(needle) {
    // Per spec, the way to identify NaN is that it is not equal to itself
    var findNaN = needle !== needle;
    var indexOf;

    if(!findNaN && typeof Array.prototype.indexOf === 'function') {
        indexOf = Array.prototype.indexOf;
    } else {
        indexOf = function(needle) {
            var i = -1, index = -1;

            for(i = 0; i < this.length; i++) {
                var item = this[i];

                if((findNaN && item !== item) || item === needle) {
                    index = i;
                    break;
                }
            }

            return index;
        };
    }

    return indexOf.call(this, needle) > -1;
};

var myArray = [0,1,2],
    needle = 1,
    index = contains.call(myArray, needle); // true
console.log(index);

Cgt4-0_console_dump.txt

Native Browser JavaScript
true