The principle and simple usage of JS prototype

• In JS, each object has its prototype object, and it can use all the methods on its prototype object
• Obtain the prototype object method through the object _proto_, or get the prototype through the prototype attribute
• Role: add methods to the prototype to achieve reuse, etc.

let data = new Date();
Date.prototype.formate = function(){
    
    
	let year = this.getFullYear();
	let month = this.getMonth()+1;
	let date= this.getDate();
	return `${
      
      year}年${
      
      month}月${
      
      date}日`
}