JSFiddle - React, Tailwind, and code Playground

JavaScript

function Person(name){
    this._name = name;
    this.doSomething = function () {
        console.log('doSomething');
     }
}

function Student (name, grade) {
    Person.call(this, name, grade); // extends
    this._name = name;
    this._grade = grade;

    this.hello = function  () {
        this.doSomething();
    }
}

var student = new Student("test","A")
student.hello();