Why Object.assign does not work properly in Jest?

Asked Feb 04 '22 at 14:38

Active Feb 04 '22 at 14:38

Viewed 21 times

somefile.unit.test.js //jest unit test file

import pageData from '../__mocks__/somefile.mock.json';
...
describe('My component', () => {
  it('Test 1', async () => {
    const page = Object.assign({}, pageData);
    page.someprop = 'baboon';
  });
  it('Test 2', async () => {
    const page = Object.assign({}, pageData);
    console.log(page.someprop); //baboon
  });
});

I want imported objects will be immutable. Trying to clone it with "Object.assign", but for some reason, pageData does not clone and by changing "page" i do change "pageData" at the same time.

Why Object.assign does not work in Jest? ( I've tried jest.unmock('object-assign') )

asked Feb 04 '22 at 14:38

Artem Reva

Are you actually changing it on the first level and not a nested property? `page.foo.someprop` ? – epascarello Feb 04 '22 at 14:40
I would be quite surprised if your example actually behaved the way you say it does. – Pointy Feb 04 '22 at 14:42
Willing to bet my comment is correct and it is a dupe of https://stackoverflow.com/questions/34504682/js-does-object-assign-create-deep-copy-or-shallow-copy – epascarello Feb 04 '22 at 14:42
You right @epascarello my bad. Thank you. – Artem Reva Feb 04 '22 at 14:51

Why Object.assign does not work properly in Jest?

0 Answers0