Function forEach

test/blanket_mocha.js:3926–3931

(xs, fn)

    return keys;
};
var forEach = function (xs, fn) {
    if (xs.forEach) return xs.forEach(fn);
    for (var i = 0; i < xs.length; i++) {
        fn.call(xs, xs[i], i, xs);
    }
};

var isArray = Array.isArray || function (xs) {
    return Object.prototype.toString.call(xs) === '[object Array]';