Method heapifyUp

src/data-structures/heap/Heap.js:223–236

* @param {number} [customStartIndex]

(customStartIndex)

   * @param {number} [customStartIndex]
   */
  heapifyUp(customStartIndex) {
    // Take the last element (last in array or the bottom left in a tree)
    // in the heap container and lift it up until it is in the correct
    // order with respect to its parent element.
    let currentIndex = customStartIndex || this.heapContainer.length - 1;

    while (
      this.hasParent(currentIndex)
      && !this.pairIsInCorrectOrder(this.parent(currentIndex), this.heapContainer[currentIndex])
    ) {
      this.swap(currentIndex, this.getParentIndex(currentIndex));
      currentIndex = this.getParentIndex(currentIndex);
    }
  }

  /**
   * @param {number} [customStartIndex]