atriusmaps-node-sdk/dist/cjs/plugins/wayfinder/src/minPriorityQueue.js

This project provides an API to Atrius Personal Wayfinder maps within a Node environment. See the README.md for more information

'use strict';

class MinPriorityQueue {
  constructor() {
    this.heap = [null];
    this.heapMap = {};
  }
  offerWithPriority(node, priority) {
    const index = this.heap.push([node, priority]) - 1;
    this.heapMap[node] = index;
    this.bubble(index);
  }
  raisePriority(node, priority) {
    const index = this.heapMap[node];
    this.heap[index][1] = priority;
    this.bubble(index);
  }
  poll() {
    if (this.heap.length === 1) {
      return null;
    }
    if (this.heap.length === 2) {
      const value2 = this.heap.pop()[0];
      delete this.heapMap[value2];
      return value2;
    }
    const value = this.heap[1][0];
    delete this.heapMap[value];
    this.heap[1] = this.heap.pop();
    this.heapMap[this.heap[1][0]] = 1;
    this.sink(1);
    return value;
  }
  isEmpty() {
    return this.heap.length === 1;
  }
  bubble(i) {
    while (i > 1) {
      const parentIndex = i >> 1;
      if (!this.isHigherPriority(i, parentIndex)) {
        break;
      }
      this.swap(i, parentIndex);
      i = parentIndex;
    }
  }
  sink(i) {
    while (i * 2 < this.heap.length) {
      const isRightChildHigherPriority = this.heap[i * 2 + 1] === void 0 ? false : this.isHigherPriority(i * 2 + 1, i * 2);
      const childIndex = isRightChildHigherPriority ? i * 2 + 1 : i * 2;
      if (this.isHigherPriority(i, childIndex)) {
        break;
      }
      this.swap(i, childIndex);
      i = childIndex;
    }
  }
  swap(i, j) {
    this.heapMap[this.heap[i][0]] = j;
    this.heapMap[this.heap[j][0]] = i;
    const temp = this.heap[i];
    this.heap[i] = this.heap[j];
    this.heap[j] = temp;
  }
  isHigherPriority(i, j) {
    return this.heap[i][1] < this.heap[j][1];
  }
}

module.exports = MinPriorityQueue;