A queue implementation in JavaScript that doesn't suck. Note that the search-based retrieval algorithm is O(n) but 'dequeue' is O(1) so the overall search speed is O(n) where it would've been O(n**2) if I used Array.shift() to perform the 'dequeue' step. Feedback welcome.

playerqueue.js

var QueueElement = function(playerInfo) {
  this.name = playerInfo.name;
	this.rank = playerInfo.rank;
	this.last_seen = playerInfo.last_seen;
	this.next = undefined;
	this.prev = undefined;
}

var head = undefined,
	queue_size = 0;

exports = {
	addPlayer: function(playerInfo) {
		if(head == undefined) {
			head = new QueueElement(playerInfo);
			head.next = head;
			head.prev = head;
		} else {
			var newElement = new QueueElement(playerInfo);
			newElement.next = head;
			newElement.prev = head.prev;
			head.prev = newElement;
		}
		queue_size++;
	},
	seekPlayer: function(rank,error_margin) {
		var current_element;
		for(var i = 0; i < queue_size; i++) {
			if(current_element.rank <= rank + error_margin / 2 && current_element.rank >= rank - error_margin / 2) {
				dequeue(current_element);
				return current_element;
			}
		}
		return undefined;
	},
	dequeue: function(element) {
		var next = element.next,
			prev = element.prev;
		prev.next = next;
		next.prev = prev;
		element = undefined;
	}
};