Elegant memoizing

Question

I wanted an elegant way to implement memoizing. Here is what I came up with:

function memoize(fn) {
    var cache = new WeakMap();
    return function() {
        if (!cache[arguments]) {
            cache[arguments] = fn.call(this, arguments);
        }
        return cache[arguments];
    }
}

It's quite nice, but the WeakMap is not well supported. Is there a better, yet clean way to do this?

Answer 1

I just thought about this:

function memoize(fn) {
    var cache = {};
    return function() {
        var args = Array.prototype.slice.call(arguments).toString();
        if (!cache[args]) {
            cache[args] = fn.call(this, arguments);
        }
        return cache[args];
    }
}

It's very cross-browser. I can't think of any browser not supporting this.

But it does feel kind of ugly. It's still the best I can think of though.