[JavaScript知识库]基于js数组和js对象的Stack类

基于js数组的Stack类

      class Stack {
        constructor() {
          this.items = [1, 2, 3]
        }
        //向栈添加元素
        push(element) {
          this.items.push(element)
        }
        //移除栈顶元素
        pop() {
          return this.items.pop()
        }
        //查看栈顶元素
        peek() {
          return this.items[this.items.length - 1]
        }
        //检查栈是否为空
        isEmpty() {
          return this.items.length === 0
        }
        //栈的长度
        size() {
          return this.items.length
        }
        //清空栈
        clear() {
          this.item = []
        }
      }
      var stack = new Stack()
      console.log(stack)

基于js对象的Stack类

      class Stack {
        constructor() {
          this.count = 0
          this.items = {}
        }
        //插入元素
        push(element) {
          this.items[this.count] = element
          this.count++
        }
        //查看栈的大小
        size() {
          return this.count
        }
        //查看栈是否为空
        isEmpty() {
          return this.count == 0
        }
        //从栈中弹出元素
        pop() {
          if (this.isEmpty()) {
            return undefined
          }
          this.count--
          const result = this.items[this.count]
          delete this.items[this.count]
          return result
        }
        //查看栈顶的值
        peek() {
          if (this.isEmpty()) {
            return undefined
          }
          return this.items[this.count - 1]
        }
        //清空栈
        clear() {
          this.count = 0
          this.items = {}
        }
        //创建toString()方法
        toString() {
          if (this.isEmpty()) {
            return ''
          }
          let objString = `${this.items[0]}`
          for (let i = 1; i < this.count; i++) {
            objString = `${objString},${this.items[i]}`
          }
          return objString
        }
      }
      var stack = new Stack()
      stack.push(3)
      stack.push(4)
      console.log(Object.getOwnPropertyNames(stack)) //['count', 'items']
      console.log(Object.keys(stack)) //['count', 'items']
      console.log(stack.count, stack.items) //2 {0: 3, 1: 4}