Immutable Hash and Array implementation in JavaScript?

Question

Is there simple immutable hash and array implementation in javascript? I don\'t need best speed, a reasonable speed better than a clone would be good.

Answer 1

The only way to make an object immutable is to hide it inside a function. You can then use the function to return either the default hash or an updated version, but you can't actually store an immutable hash in the global scope.

function my_hash(delta) {
    var default = {mykey: myvalue};
    if (delta) {
        for (var key, value in delta) {
            if (default.hasOwnProperty(key)) default[key] = value;
        }
    }
    return default;
}

I don't think this is a good idea though.