materials

栈是一种遵循后进先出（LIFO）原则的有序集合。新添加或待删除的元素都保存在栈的同一端，称作栈顶，另一端就叫栈底

创建一个类来表示数组

class Stack {
    constructor(){
        this.items = [];
    }
    push(element){
        this.items.push(element)
    }
    pop(element){
        this.items.pop();
    }
    peek(element){
        return this.items[this.items.length-1]
    }
    isEmpty(){
        return this.items.length === 0
    }
    clear(){
        this.items = []
    }
    size(){
        return this.items.length
    }
}
let stack = new Stack();
stack.push(1)
console.log(stack.size())
console.log(stack.isEmpty())

创建一个基于Javascript对象的Stack类

class Stack {
    constructor(){
        this.items = [];
    }
    push(element){
        this.items.push(element)
    }
    pop(){
        this.items.pop();
    }
    peek(){
        return this.items[this.items.length-1]
    }
    isEmpty(){
        return this.items.length === 0
    }
    clear(){
        this.items = []
    }
    size(){
        return this.items.length
    }
}
let stack = new Stack();
stack.push(1)
console.log(stack.size())
console.log(stack.isEmpty())
class Stack1{
    constructor(){
        this.count = 0;
        this.items = {}
    }
    push(element){
        this.items[this.count] = element;
        this.count++
    }
    pop(){
        if(this.isEmpty()){
            return undefined
        }
        this.count--;
        const result = this.items[this.count]
        delete this.items[this.count]
        return result;
    }
    peek(){
        return this.items[this.count-1]
    }
    size(){
        return this.count;
    }
    isEmpty(){
        return this.count ===0
    }
    clear(){
        this.count = 0;
        this.items = {}
    }
    toString(){
        if(this.isEmpty()){
            return ''
        };
        let objString = `${this.items[0]}`;
        for (let i=0;i<this.count;i++){
            objString = `${objString},${this.items[i]}`
        }
        return objString
    }
}
let a = new Stack1();
a.push(1);
console.log(Object.getOwnPropertyNames(a))
console.log(Object.keys(a))

https://juejin.cn/post/6844903757973569544