stack data structure

stack.js

function createStack() {
  const stack = [];

  return {
    push(item) {
      stack.push(item)
    },
    
    pop() {
      return stack.pop()
    },
    
    peek() {
      return stack[stack.length - 1]
    },
    
    get length() {
      return stack.length
    },
    
    isEmpty() {
      return stack.length === 0
    }
  }
}