JS: Queue Implementation

queue.js

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

  enqueue(obj) {
    this.items.push(obj);
  }

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

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

var queue = new Queue();

console.assert(queue._items.length == 0)

queue.enqueue('foo');
queue.enqueue('bar');
queue.enqueue('baz');

console.assert(queue._items.every((v,i) => 
    v === ['foo', 'bar', 'baz'][i]
))

queue.dequeue();

console.assert(queue._items.every((v,i) => 
    v === ['bar', 'baz'][i]
));