stack - 2

class Stack {
  constructor() {
    this.data = {}
    this.size = 0
  }
  
         // add an element
         
  push(element) {
    this.size++
    this.data[this.size] = element
  }
  
        // remove last element
        
  pop(element) { 
    let removed = this.data[this.size]
    delete this.data[this.size]
    this.size--
    return removed
  }
  
        // look at the last element
          
  peek() { 
    return this.data[this.size]
  }
  
        // is the stack empty ?
        
  isEmpty() {
    return this.size === 0
  }
}