CODEWITHSUNDEEP
javascriptecmascript-6
John Abraham
John Abraham

Reputation: 18781

Is it possible in es6 to instantiate a class and define prototype properties similar to a classical constructor?

In ES6 when you create a class with prototype properties how can I set those props baz and biz on instantiation (new) of class?

class Foo {}

Foo.prototype.baz = 1;
Foo.prototype.biz = 'wow';

var thing = new Foo() // How to also set prototype values of .baz & .biz on creation?



class Baz {

  constructor(biz) {
   this.biz = biz
  }
}

var baz = new Baz(); // will not put properties on the prototype.

Upvotes: 1

Views: 214

Answers (2)

Estus Flask
Estus Flask

Reputation: 222493

It is

class Baz {
  constructor(biz) {
    Object.getPrototypeOf(this).biz = biz
    // or
    // this.constructor.prototype.biz = biz
  }
}

const baz1 = new Baz(1); // baz1.biz === 1
const baz2 = new Baz(2); // baz2.biz === 2
baz1.biz === baz2.biz; // === 2

And it is not something the one would want to do in any reasonable scenario.

Upvotes: 2

Bergi
Bergi

Reputation: 664538

Yes, you can set prototype properties just like that, just like we did without using class syntax.

How to also set prototype value on creation?

You cannot. Prototypes have nothing to do with instantiation. If you want instance properties, put them in the constructor, but they won't be prototype properties any more. If you want inherited properties, put them on the prototype, but they're shared between all instances and not created with every object.

Upvotes: 1

Related Questions