Unit testing with Jest without module.exports

Question

I have a script that holds a single const variable which holds all of my logic, kind-of like Moment.js.
I want to test out functions that go out with this script with Jest.

I can't use module.exports since it will not work when I publish my script.
And if I can't use module.exports I can't use require.

But I still want to run unit tests on my script.
I have tried using import with no luck.

Here is my code:

import 'src/library.js';

test('Something', () => {
    expect(library.add(1,2)).toBe(3);
});

And this is my library:

const library = () => {
    return {
        add : (num1,num2) => num1 + num2,
        subtract : (num1,num2) => num1 - num2
    }
}

score 10 · Accepted Answer · answered Apr 03 '19 at 21:21

10

what about wrapping your exports with:

if (typeof exports !== 'undefined') {
    module.exports = { yourWhatever };
}

answered Apr 03 '19 at 21:21

more urgent jest

362
4
11

Great one. It will be helpful when the client does not approve of us using other libraries like Webpack and Babel or for any other reason. Caveat: It looks like a code smell. – Carlos Querioz Nov 06 '21 at 17:01

score 0 · Answer 2 · answered Sep 25 '18 at 20:31

0

First Option (Quick & Dirty): Don't import. Just move the code into one file.

Second Option (Best Long Term): Learn how to use (webpack and) babel.

answered Sep 25 '18 at 20:31

Geoffrey Hale

10,597
5
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45

Come to think of it, I could use gulp to merge both files (test one and library one). – Nir Tzezana Sep 25 '18 at 20:34
1

Neither of these options solve the original problem asked within constrains asked. – SbnSeebee Nov 18 '21 at 22:49

Unit testing with Jest without module.exports

2 Answers2