Apps Script Queue Implementation

queue.gs

/**
 * @class
 * Class representing an Item in a Queue
 * 
 * @author russellsimpkins@gmail.com
 */
class Item {
  constructor(v) {
    this.v = v;
    this.n = null;
  }
  val() {
    return this.v;
  }
  setNext(i) {
    this.n = i;
  }
  next() {
    return this.n;
  }
}

/**
 * @class
 * Class representing a Queue
 * 
 * This is a basic linked list impelemetion for a FIFO queue.
 * 
 * @author russellsimpkins@gmail.com
 */
class Queue {
  constructor(item) {
    if (undefined == item) {
      this.items = 0;
      this.start = null;
      this.end = null;
      this.item = null;
      return;
    }
    this.items = 1;
    this.item = item;
    this.start = item;
    this.end = item;
  }
  add(item) {
    if (this.items == 0) {
      this.items = 1;
      this.item = item;
      this.start = item;
      this.end = item;
    } else {
      this.items++;
      let tail = this.end;
      tail.setNext(item);
      this.end = item;
    }
  }
  pop() {
    let item = this.start;
    if (null != item.next()) {
      this.start = item.next();
    }
    this.items--;
    return item;
  }
}