extends_class.js

class Human {
  constructor () {
    this.gender = 'Male';
  }
  printGender() {
    console.dir(this.gender);
  }
}

//The extends keyword means 
//we are inheriting from the Human

class Person extends Human {
  
  constructor () {
    //we have to call the super constructor
    super();
    
    this.name = 'Abel';
  }

  printMyName() {
    console.dir(this.name);
  }
  
}

//We can call the class like below::
const person = new Person();

person.printMyName(); //we return 'Abel';
person.printGender(); //we console 'Male';