Heap and priority queue in JavaScript

class MinHeap {
  constructor() {
    this.heap = [];
  }

  push(val) {
    this.heap.push(val);
    this.bubbleUp(this.heap.length - 1);
  }

  bubbleUp(index) {
    while (index > 0) {
      const parent = Math.floor((index - 1) / 2);
      if (this.heap[parent] <= this.heap[index]) break;
      [this.heap[parent], this.heap[index]] = [this.heap[index], this.heap[parent]];
      index = parent;
    }
  }
}