ES6 javascript inheritance

Question

Provided the following code:

class Person {
    constructor(name) {
        this.name = name;
    }
    sayHello() {
        console.log('Hello, my name is ' + this.name);
    }
    sayHelloAndBy() {
        this.sayHello();
        console.log('Bye');
    }

}
class Student extends Person {
    constructor(name, grade) {
        super(name);
        this.grade = grade;
    }
    sayHello() {
        console.log(`Hi, I'm a studend and my name is ` + this.name);
    }
}


let b = new Student("Some guy", 5);

b.sayHelloAndBy();

I would like to figure out a way of calling sayHello as defined in Person and not in Student . Is it possible ?

In php there is the self:: which allows one to do this, but I'm not sure if JS has a similar concept.

Answer 1

You can refer to the version of sayHello defined in Person through Person 's prototype property and call it with the requisite this using Function#call :

sayHelloAndBye() {
    Person.prototype.sayHello.call(this);
    console.log('Bye');
}

Runnable:

 class Person { constructor(name) { this.name = name; } sayHello() { console.log('Hello, my name is ' + this.name); } sayHelloAndBye() { Person.prototype.sayHello.call(this); console.log('Bye'); } } class Student extends Person { constructor(name, grade) { super(name); this.grade = grade; } sayHello() { console.log(`Hi, I'm a studend and my name is ` + this.name); } } let b = new Student("Some guy", 5); b.sayHelloAndBye();