Implemented a basic extraction loop

lib/priority_queue.js

@@ -0,0 +1,39 @@
+export class QElement {
+	constructor(element, priority) {
+		this.element = element;
+		this.priority = priority;
+	}
+}
+
+export class PriorityQueue {
+	constructor(elt) {
+		this.items = [];
+		if (elt !== undefined) {
+			this.enqueue(elt, 0);
+		}
+	}
+
+	enqueue(element, priority) {
+		let qElement = new QElement(element, priority);
+
+		for (let i = 0; i < this.items.length; ++i) {
+			if (this.items[i].priority > qElement.priority) {
+				this.items.splice(i, 0, qElement);
+				return;
+			}
+		}
+		this.items.push(qElement);
+	}
+	dequeue() {
+		return this.items.shift(); // we would use pop to get the highest priority, shift() gives us the lowest priority
+	}
+	front() {
+		return this.items[0];
+	}
+	rear() {
+		return this.items[this.items.length - 1];
+	}
+	isEmpty() {
+		return this.items.length === 0;
+	}
+}