Inheritance In ES6

Classes In ES6

Implementing a Class

• to Implement a class we use the class keyword.
• every class must have a constructor function. attributes of that class are defined using getters/setters(functions as well).
• as for attributes we use getters and setters.
• getter and setter are special kind of methods that allow us to set the value of an attribut, and get the values of an attribute.

class Person {
  //getter
  //here we used the get keyword and then the name of the getter
  get Name() {
    return this.name; //here we simply return the value of that attribute but with the this key word
    //so that we get the attribute of the select instance of that class
  }
  //setter
  set Name(name_) {
    //and here we set the value of the attribute
    this.name = name_;
  }
  //getter
  get Age() {
    return this.age;
  }
  //setter
  set Age(age_) {
    this.age = age_;
  }
  //constructor
  constructor(name_, age_) {
    this.name = name_;
    this.age = age_;
    this.canWalk = function() {
      console.log("YAY !! I'm Walking");
    };
  }
}

//this is an instance of a Person
let me = new Person("salah", 25);
console.log(me); //Person {name:'salah',age:25}

console.log(me.Age); //getter
me.Age = 22; //setter
console.log(me.Name); //getter
me.Name = "SALAH EDDINE"; //setter

console.log(me); //Person {name:'SALAH EDDINE',age:22}

Inheritance

• In modern javascript we have the extends key work which makes easier to implement
• inheritance in between our classes.
• Male extends Person means that Male class has all the properties and methods of Person And also have it's own.

class Male extends Person {
  //getter
  get Gender() {
    return this.gender;
  }
  constructor(name_, age_ /*,here we can add other attributes as well*/) {
    //in the child class(Male) we must call the parent constructor first
    //we do that using the super method and pass to it age_ and name_ parent properties
    super(name_, age_);
    //and now we assign the child property gender which in this case will have a fixed value
    this.gender = "male";
  }
}

//this is an instance of a male
let MalePerson = new Male("mohammed", 15);
console.log(MalePerson); //Male{name:'mohammed',age:15,gender:''male}