generic queue that applies the passed operation to each element, separating each call out by the specified throttle

queue.js

function Queue(config) {
    this.throttle    = (typeof config['throttle'] !== "undefined") ? config['throttle'] : 2000;
    this.elements    = config['elements'];
    this.operation   = config['operation'];
    this.interval_id = null;
 
    return this;
}

Queue.prototype.process = function() {
    var self = this;
    
    this.interval_id = window.setInterval(function() {
        self.operation(self.elements.shift());
        if (self.elements.length <= 0) { self.halt(); }
    }, this.throttle);
}

Queue.prototype.halt = function() {
    clearInterval(this.interval_id);
    this.log("halted interval " + this.interval_id);
    this.interval_id = null;
}

Queue.prototype.log = function(msg) {
    console.log("[" + new Date + "] " + msg);
}

ex:

var elements = [1, 2, 3, 4];
var operation = function(element) {
    console.log("[" + new Date + "] element " + element + " times 2 = " + element * 2);
}

q = new Queue({elements: elements, operation: operation});
q.process();
/*
output ...
[Sun Jun 23 2013 14:07:06 GMT-0700 (PDT)] element 1 times 2 = 2
[Sun Jun 23 2013 14:07:08 GMT-0700 (PDT)] element 2 times 2 = 4
[Sun Jun 23 2013 14:07:10 GMT-0700 (PDT)] element 3 times 2 = 6
[Sun Jun 23 2013 14:07:12 GMT-0700 (PDT)] element 4 times 2 = 8
[Sun Jun 23 2013 14:07:12 GMT-0700 (PDT)] halted interval 3 
*/