lintified_filter.js

if (!Array.prototype.filter) {
    Array.prototype.filter = function (fun, thisp) {
        "use strict";

        if (typeof this === "undefined" || this === null) {
            throw new TypeError();
        }
        if (typeof fun !== "function") {
            throw new TypeError();
        }

        thisp = thisp || this;

        var t = this.slice(),
            len = t.length,
            res = [],
            i,
            val;

        for (i = 0; i < len; i += 1) {
            if (typeof t[i] === "undefined") {
                val = t[i]; // in case fun mutates this
                if (fun.call(thisp, val, i, t)) {
                    res.push(val);
                }
            }
        }

        return res;
    };
}