FE_JS class definition and use

What is a class? In the program, the unified attribute structure and method definition of all sub-instances of a type are specially stored in a program structure. How to define class? The native definition of js:

    function Student(name,age){
    
    
      this.name= name ;
      this.age = age;
    }
    Student.prototype.intr= function(){
    
    
        console.log(`我叫${
      
      this.name};我今年${
      
      this.age}岁`)
    }
    var person = new Student('张三',18)
    person.intr(); //我叫张三;我今年18岁

Use class definition:

• Wrap the original constructor + prototype object method with class{}
• The original constructor name is upgraded to the name of the entire class, and all constructors are renamed to constructor
• The method in the prototype object does not need to be prefixed with prototype or =function, and is directly abbreviated as: method name (){ ... ...}

    class Student {
    
    
        constructor(name, age) {
    
    
            this.name = name;
            this.age = age;
        }

        intr() {
    
     // 自动放入原型对象中
            console.log(
                `我叫${
      
      this.name}, 我${
      
      this.age}岁`);
        }
    }

    var person = new Student('张三', 18)
    person.intr(); //我叫张三;我今年18岁

Question: Where are the method definitions inside class{} stored? Result: They are all stored on the prototype object; their essence is the same, and the data structure that appears after printing person is the same.

Question: If the same attribute value is shared by multiple sub-objects, where should it be placed? How to access
Shared property placement: static className=“Senior One (2) Class”
Shared property access: Student.className

class{
    
    
    constructor(name, age) {
    
    
        this.name = name;
        this.age = age;
      }
    static className="高一（2）班"  // static 共有属性名=属性值
    intr() {
    
     // 自动放入原型对象中
        console.log(
          `我叫${
      
      this.name}, 我${
      
      this.age}岁`,${
    
    Student.className});
      }
    }
}

The use of extends and super in class:

    class people {
    
    
        constructor(name, sex, age) {
    
    
            this.name = name;
            this.sex = sex;
            this.age = age;
        }

        peopleAction() {
    
    
            console.log(`我叫${
      
      this.name},我是${
      
      this.sex},我今年${
      
      this.age}岁`)
        }
    }

    class men extends people {
    
    
        constructor(name, sex, age, noBirthBaby) {
    
    
            super(name, sex, age)
            this.noBirthBaby = noBirthBaby;
        }

        action() {
    
    
            console.log(`我叫${
      
      this.name},我是${
      
      this.sex},我今年${
      
      this.age}岁,我${
      
      this.noBirthBaby}生娃`)
        }
    }

    var tom = new men('Tom', '男', '5', '不会')
    tom.peopleAction() //我叫Tom,我是男,我今年5岁 --使用父类的方法
    tom.action()  //我叫Tom,我是男,我今年5岁,我不会生娃

    var Mill = new men('Mill', '女', '21', '会')
    Mill.action() //我叫Mill,我是女,我今年21岁,我会生娃