Ordered hash in JavaScript

Question

JavaScript objects have no order stored for properties (according to the spec). Firefox seems to preserve the order of definition of properties when using a for...in<

Answer 1

Taking @Craig_Walker solution, if you are only interested to know in which order the properties have been inserted, an easy solution would be :

var obj ={ }
var order = [];

function add(key, value) {
    obj[key] = value;
    order.push(key);
}

function getOldestKey() {
    var key = order.shift();
    return obj[key]
}

function getNewsetKey() {
    var key = order.pop();
    return obj[key]
}