A class can extends the definition of another class, and a new object initialized from that class will have all the methods of both classes. The class that extends another class is usually called child class or sub class, and the class that is being

ES6.class.inheritance.ex1.js

class ReactDeveloper extends Developer {
  installReact(){
    return 'installing React .. Done.';
  }
}

var nathan = new ReactDeveloper('Nathan');
nathan.hello(); // Hello World! I am Nathan and I am a web developer
nathan.installReact(); // installing React .. Done.

ES6.class.inheritance.ex2.js

class ReactDeveloper extends Developer {
  installReact(){
    return 'installing React .. Done.';
  }

  hello(){
    return 'Hello World! I am ' + this.name + ' and I am a REACT developer';
  }
}

var nathan = new ReactDeveloper('Nathan');
nathan.hello(); // Hello World! I am Nathan and I am a REACT developer

ES6.class.inheritance.React.js

//Now that we understand ES6 class and inheritance, we can understand the React class defined in src/app.js. This is a React component, but it's actually just a normal ES6 class which inherits the definition of React Component class, which is imported from the React package.
//Everytime we need variables. Consider the following example:
import React, { Component } from 'react';

class App extends Component {
  // class content
  render(){
    const greeting = 'Welcome to React';
    return (
      <h1>{greeting}</h1>
    )
  }
}

//This is what enables us to use the render() method, JSX, this.state, other methods. All of this definitions are inside the Component class. But as we will see later, class is not the only way to define React Component. If you don't need state and other lifecycle methods, you can use a function instead.