Coding Exercise - Queue From Stacks

two_stacks_one_queue.js

/*
Implement a Queue data structure using two stacks.
- Do not create an array inside of the 'Queue' class.
- Queue should implement the methods 'add', 'remove', and 'peek'.
*/

class Stack {
  constructor() {
    this.data = [];
  }

  push(record) {
    this.data.push(record);
  }

  pop() {
    return this.data.pop();
  }

  peek() {
    return this.data[this.data.length - 1];
  }
}

class Queue {
    constructor() {
        this.dataOne = new Stack();
        this.dataTwo = new Stack();
    }
    
    add(item) {
        this.dataOne.push(item);
    }
    
    remove() {
        while(this.dataOne.peek()) {
            this.dataTwo.push(this.dataOne.pop());
        }
        
        const item = this.dataTwo.pop();
        
        while (this.dataTwo.peek()) {
            this.dataOne.push(this.dataTwo.pop())
        }
        
        return item;
    }
    
    peek() {
        while(this.dataOne.peek()) {
            this.dataTwo.push(this.dataOne.pop());
        }
        
        const item = this.dataTwo.peek();
        
        while (this.dataTwo.peek()) {
            this.dataOne.push(this.dataTwo.pop())
        }
        
        return item;
    }
}