Set object

gistfile1.js

var Set = function() {
    this.items = {};
    this.add = function(key) {
        this.items[key] = true;
    }
    this.exists = function(key) {
        return this.items.hasOwnProperty(key);
    }
    this.as_array = function() {
        var keys = [];
        console.log(this);
        jQuery.each(this.items, function(key){
            keys.push(key);
        });
        return keys;
    }
    this.remove = function(key) {
        delete this.items[key];
    }
    return this;
}