Javascript How to create object of multiple class at one time

Question

I am new to Javascript ES6 class, i want to create object of multiple class at one time. does it is possible. below is my example

This file is in A.js

module.exports= class A{
 constructor(url){
    this.url = url;

  }
}

This file is in B.js

module.exports= class B{
 constructor(url){
    this.url = url;

  }
}

need to create instance of class A and class B at same time calling from different file ex: DE.js and return that instance

What is your specific use case? What are you trying to achieve? — christopher, Jun 17 '18 at 08:37
`const a = new A(url); const b = new B(url);` ? Or do you wanna achieve multi inheritance? — Jonas Wilms, Jun 17 '18 at 08:37
i have to create separate file and i need to return the class A and Class B obeject instance — crypto money, Jun 17 '18 at 08:39
`var func = (url) => { return {A: new A(url), B :new B(url)} }` — Shankar Shastri, Jun 17 '18 at 08:45
yes, suppose i have multiple js file like A.js, B.js,and i have multiple class inside of each file, now i need to create one file, So i can include all js file like A.js B.js and create instance of class A inside of A.js and class B inside of B.js and can access the all the method of each class — crypto money, Jun 17 '18 at 08:46
Again, what is your specific use case? This abstraction is confusing the issue. I suspect there is a more elegant solution but you'll only get there if you're willing to share _why_ you want to do this. — christopher, Jun 17 '18 at 08:47
@cryptomoney https://stackoverflow.com/questions/38340500/export-multiple-classes-in-es6-modules — Shankar Shastri, Jun 17 '18 at 08:48

Jonas Wilms · Accepted Answer · 2018-06-17T09:16:06.523

1

Javascript has single inheritance, that means that every instance only has one prototype, so this:

instance -> A
          -> B

Is not possible. However we could create a copy of B, lets call it _B that inherits A, so we can create elements from that class that inherit both A and B:

instance -> _B -> A

We could create that class _B like this:

const Compose = (A, B) => {
  class _B extends A { // extend A
     constructor(...args) {
        super(...args); // construct A
        Object.assign(this, new B(...args)); // construct B
     }
   }

   // Copy B into _B
  Object.getOwnPropertyNames(B.prototype)
    .forEach(key => _B.prototype[key] = B.prototype[key]);

   return _B;
};

So we can just get our new class like this:

const AandB = Compose(A, B);
const instance = new AandB("http://example.com");

edited Jun 17 '18 at 09:16

answered Jun 17 '18 at 08:52

Jonas Wilms

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[Try it](http://jsbin.com/mowewogage/edit?console) – Jonas Wilms Jun 17 '18 at 09:17
I still don't get the question. Suggesting multiple inheritance as a solution is hardly helpful. – Bergi Jun 17 '18 at 09:30
@bergi yes I considered to vote for closing, but I'm not sure if thats more helful either. – Jonas Wilms Jun 17 '18 at 09:33

Javascript How to create object of multiple class at one time

1 Answers1