Simple way to map anything to anything.
Kind of a hash map.
JavaScript
var aliases = {};
function User(name) {
this._name = name;
}
User.prototype.toString = function() {
// You could probably use some kind of UID instead.
// It just has to be a unique identifier of any kind.
return this.constructor.name + ':' + this._name;
};
var someUser = new User('Oliver Caldwell');
aliases[someUser] = 'Wolfy87';
console.log(aliases);