Can you export multiple classes from a single Nodejs Module?

Question

Currently, I have 4 Child Classes each in their own file. I'm requiring them all in the same file. I am wondering if I can contain all 4 of those classes in a single module. Currently, I'm importing them like this

var Jack = require('./Jack.js');
var JackInstance = new Jack();
var Jones = require('./Jones.js');
var JonesInstance = new Jones();

I'd like to import them like this

var People = require('./People.js');
var JackInstance = new People.Jack();

Or even

var Jack = require('./People.js').Jack;
var JackInstance = new Jack();

My classes are defined like so

class Jack{
    //Memeber variables, functions, etc
}

module.exports = Jack;

Solution 1

You can export multiple classes like this:

e.g. People.js

class Jack{
   //Member variables, functions, etc
}

class John{
   //Member variables, functions, etc
}

module.exports = {
  Jack : Jack,
  John : John
}

And access these classes as you have correctly mentioned:

var People = require('./People.js');
var JackInstance = new People.Jack();
var JohnInstance = new People.John();

Solution 2

You can also do this in a shorter form, using destructuring assignments (which are supported natively starting from Node.js v6.0.0):

// people.js

class Jack {
  // ...
}

class John {
  // ...
}

module.exports = { Jack, John }

Importing:

// index.js

const { Jack, John } = require('./people.js');

Or even like this if you want aliased require assignments:

// index.js

const {
  Jack: personJack, John: personJohn,
} = require('./people.js');

In the latter case personJack and personJohn will reference your classes.

A word of warning:

Destructuring could be dangerous in sense that it's prone to producing unexpected errors. It's relatively easy to forget curly brackets on export or to accidentally include them on require.

---

Node.js 12 update:

Lately ECMAScript Modules received an extended support in Node.js 12.*, introducing the convenient usage of import statement to accomplish the same task (currently Node should be started with a flag --experimental-modules in order to make them available).

// people.mjs

export class Jack {
  // ...
}

export class John {
  // ...
}

Notice that files that adhere to modules convention should have an .mjs extension.

// index.mjs

import {
  Jack as personJack, John as personJohn,
} from './people.mjs';

This is much better in a sense of robustness and stability, as an attempt to import non-existing export from the module will throw an exception similar to:

SyntaxError: The requested module 'x' does not provide an export named 'y'

Comments

[Native Coder]

REALLY!? I tried this exact method earlier! Let me try again. I'll accept your ans asap.

[Native Coder]

As it turns out, I just had a typo. Thanks!!

[Shashi]

@MukeshSharma: I want class Jack and John will be in a separate file like jack.js and john.js...then will require people.js and want to access jack instance using people.jack. could you please help?

[Ridhwaan Shakeel]

would destructuring work? var {John, Jack} = require('./People.js'); var JackInstance = new Jack();