高效数组去重

Array.prototype.unique = function()
{
    var n = {}, r = [], len = this.length, val, type;
    for (var i = 0; i < this.length; i++) {
        val = this[i];
        type = typeof val;
        if (!n[val]) {
            n[val] = [type];
            r.push(val);
        } else if (n[val].indexOf(type) < 0) {
            n[val].push(type);
            r.push(val);
        }
    }
    return r;
}