Priority Queue

class priorityQueue {
    constructor() {
        this.values = []
    }
    enqueue(val, priority) {
        let newNode = new Node(val, priority)
        this.values.push(newNode);
        this.bubbleUp();
    }

    bubbleUp() {
        let idx = this.values.length - 1;
        const element = this.values[idx];
        while(idx > 0) {
            let parentIdx = Math.floor((idx - 1)/2);
            let parent = this.values[parentIdx];
            if(element.priority <= parent.priority) break;
            this.values[parentIdx] = element;
            this.values[idx] = parent;
            idx = parentIdx;
        }
    }

    dequeue () {
      const min = this.values[0];
      const end = this.values.pop();
          if(this.values.length > 0) {
          this.values[0] = end;
          this.sinkDown()
      }
      return min;
    }
    sinkDown() {
        let idx = 0;
        const length = this.values.length;
        const element = this.values[0];
        while(true) {
            let leftChildIdx = 2 * idx + 1;
            let rightChildIdx = 2 * idx + 2;
            let leftChild,rightChild;
            let swap = null;
            if(leftChildIdx < length) {
                leftChild = this.values[leftChildIdx];
                if(leftChild.priority < element.priority) {
                    swap = leftChildIdx; 
                }
            }
            if(rightChildIdx < length) {
                rightChild = this.values[rightChildIdx];
                if(
                    (swap === null && rightChild.priority < element.priority) 
                                           ||
                    (swap !== null && rightChild.priority < leftChild.priority)
                 ) {
                    swap = rightChildIdx;
                } 
            }

            if(swap === null) break;
            this.values[idx] = this.values[swap]
            this.values[swap] = element;
        }
    }
}

class Node {
    constructor(val, priority) {
        this.val = val;
        this.priority = priority;
    }
}

let ER = new priorityQueue();
ER.enqueue('common cold', 5)
ER.enqueue('gunshot woind', 1)
ER.enqueue('high Fever', 4)
ER.enqueue('broken arm', 2)
ER.enqueue('glass in foot', 3)