polyfill.ts

if (Uint8Array.prototype.indexOf === undefined) {
    Uint8Array.prototype.indexOf = function (value) {
        return Array.prototype.indexOf.call(this, value);
    };
}
if (Uint8Array.prototype.slice === undefined) {
    Uint8Array.prototype.slice = function (begin, end) {
        return new Uint8Array(Array.prototype.slice.call(this, begin, end));
    };
}

if (!Uint8Array.prototype.forEach) {

    Uint8Array.prototype.forEach = function (callback/*, thisArg*/) {

        var T, k;

        if (this == null) {
            throw new TypeError('this is null or not defined');
        }

        // 1. Let O be the result of calling toObject() passing the
        // |this| value as the argument.
        var O = Object(this);

        // 2. Let lenValue be the result of calling the Get() internal
        // method of O with the argument "length".
        // 3. Let len be toUint32(lenValue).
        var len = O.length >>> 0;

        // 4. If isCallable(callback) is false, throw a TypeError exception. 
        // See: http://es5.github.com/#x9.11
        if (typeof callback !== 'function') {
            throw new TypeError(callback + ' is not a function');
        }

        // 5. If thisArg was supplied, let T be thisArg; else let
        // T be undefined.
        if (arguments.length > 1) {
            T = arguments[1];
        }

        // 6. Let k be 0.
        k = 0;

        // 7. Repeat while k < len.
        while (k < len) {

            var kValue;

            // a. Let Pk be ToString(k).
            //    This is implicit for LHS operands of the in operator.
            // b. Let kPresent be the result of calling the HasProperty
            //    internal method of O with argument Pk.
            //    This step can be combined with c.
            // c. If kPresent is true, then
            if (k in O) {

                // i. Let kValue be the result of calling the Get internal
                // method of O with argument Pk.
                kValue = O[k];

                // ii. Call the Call internal method of callback with T as
                // the this value and argument list containing kValue, k, and O.
                callback.call(T, kValue, k, O);
            }
            // d. Increase k by 1.
            k++;
        }
        // 8. return undefined.
    };
}