ES6 static method

Inheritance small practice

        {
            class Person{
                constructor(num_a,num_b){
                    this.num_a = num_a; //同绑定this
                    this.num_b = num_b;
                }                           
                sum(){ //通过this
                    return this.num_a > this.num_b ? this.num_a : this.num_b                    
                }
                newStr(){
                    return `我是最大的值${this.sum()}`
                }
            }
            let person = new Person(20,50)
            console.log(person.sum())   //输出50
        }

Static method

The former method:

1. There static keyword indicates that the method is a static method
2. Needs to be invoked through the class name instead of calling on the instance (this)
3. If you use this call, or in the use of this method. Will appear abnormal
4. Static methods and non-static method of the same name (not recommended)
5. Static methods of the parent class can be inherited by subclasses

{
            class Person{
                //实例属性新写法 写到constructor外面 顶部
                num = "新写法";   //不需要写this

                // 静 态 属 性
                // 写法(旧)： 在实例属性前， 加static关键字
                static Admin = "开机密码";            

                constructor(num_a,num_b){
                    this.num_a = num_a; //同绑定this
                    this.num_b = num_b;
                }  

               static sum(){
                    return 'hello' //内部调用 在使用静态的方法时 这里不能使用this
                }
                newStr(){

                    // console.log(`我是最大的值${Person.sum()}`) //内部调用
                    console.log(`我是最大的值${Person.sum()}和${this.num}`) 
                }
            }

            let person = new Person(20,50)

            // console.log(person.newStr())//外部调用
            person.newStr();  //内部

            console.log(Person.Admin)
  
        }