gistfile1.js

RubyArray = new JS.Class({
    include: JS.Enumerable,

    initialize: function(ary) {
        this._ary = ary;
    },

    forEach: function(block, context) {
        if (!block) return this.enumFor('forEach');
        for (var i = 0, n = this._ary.length; i < n; i++)
            block.call(context || null, this._ary[i]);
        return this;
    },

    // plus Array-specific methods
});

var a = new RubyArray([1,2,3,5])