JS Stack

stack.js

const _items = new WeakMap()

class Stack {
  constructor(value) {
    _items.set(this, []);
  }

  push(value) {
    _items.get(this).push(value);
  }

  pop() {
    const items = _items.get(this)

    if (items.length === 0 ) {
      throw new Error('Stack is empty.');
    }

    items.pop();
  }

  peek() { 
    const items = _items.get(this)

    if (items.length === 0 ) {
      throw new Error('Stack is empty.');
    }
    return items[items.length - 1]
  }

  get count() {
    return _items.get(this).length
  }

}

const stack = new Stack();