priority_queue.js

class Queue {
  constructor() {
    this._items = [];
  }

  enqueue(element) {
    if (Array.isArray(element)) {
      this._items.push(...element);
    } else {
      this._items.push(element);
    }
  }

  dequeue() {
    return this._items.shift();
  }

  front() {
    return this._items[0];
  }

  isEmpty() {
    return this._items.length === 0;
  }

  get size() {
    return this._items.length;
  }

  clear() {
    return this._items = [];
  }

  print() {
    console.log(this._items.toString());
  }
}

class PriorityQueue extends Queue {
  enqueue(element, priority) {
    if (this.isEmpty()) {
      this._items.push({
        element,
        priority,
      });
    } else {
      let added = false;
      for (let i = 0, len = this._items.length; i < len; i++) {
        if (this._items[i].priority > priority) {
          this._items.splice(i,0, {
            element,
            priority,
          });
          added = true;
          break;
        }
      }
      if (!added) {
        this._items.push({
          element,
          priority,
        });
      }
    }
  }
}