利用js中完善好的数组实现：
//push(element)
//pop(),return and delete it from stack
//peek(), return and no deletion
//size(), return number of elements
//toString(), return stack in the form of string...
//isEmpty(), return true or false
class Stack{
constructor()
{
this.data=[];
}
push(element)
{
this.data.push(element);
}
pop()
{
return this.data.pop();
}
peek()
{
return this.data[this.data.length-1];
}
isEmpty(){
return this.data.length === 0;
}
size()
{
return this.data.length;
}
toString(){
return this.data.reduce(function(acc,cur){
return acc+" "+cur.toString();
},"");
}
}
const stack=new Stack();
stack.push("maggie");
stack.push([23,45]);
stack.push(new Date().toLocaleString());
console.log(stack.toString());
stack.pop();
stack.pop();
console.log(stack.toString());
因为js的数组本身是对象，并且封装好了pop()和push()两个方法，所以直接利用这两个方法就能立刻实现栈的push()和pop()。
更加底层的实现：
const {log}=console;
//没有考虑数组扩容
function Stack(){
this.data=[];
this.top=0;
}
Stack.prototype.push=function(element){
this.data[this.top++]=element;
}
Stack.prototype.pop=function(){
return this.data[--this.top];
}
Stack.prototype.peek=function(){
return this.data[this.top-1];
}
Stack.prototype.size=function(){
return this.top;
}
Stack.prototype.isEmpty=function(){
return this.top===0;
}
Stack.prototype.toString=function(){
let tmp="";
for(let i=0;i<this.top;i++){
tmp=tmp+this.data[i];
}
return tmp;
}
const s=new Stack();
s.push(1);
s.push(0);
s.push(2);
s.push(3);
s.push(4);
log(s.toString());
s.pop();
s.pop();
s.push(5);
log(s.toString());
