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
    }
  }
}

const lowerBodyStack = createStack();

lowerBodyStack.push('underwear')
lowerBodyStack.push('socks')
lowerBodyStack.push('pants')
lowerBodyStack.push('shoes')

lowerBodyStack.pop()
lowerBodyStack.peek() // pants
lowerBodyStack.length() // 3