Jest: TypeError: Cannot redefine property: window

Question

When I run jest tests locally with yarn test:unit:watch, I am getting this error from the jest library:

Test suite failed to run

TypeError: Cannot redefine property: window

at Object.<anonymous> (node_modules/jest-canvas-mock/lib/index.js:11:17)

Any suggestion what's wrong? I tried to delete node_modules and reinstall and also to clone the repo again but it's repeating. Others are not facing this problem.

I got such an error in our own testing codebase, and was able to fix it by creating a mock implementation following this answer: https://stackoverflow.com/a/56999581 — marcw, Apr 21 '23 at 07:03

score 12 · Accepted Answer · answered Apr 21 '23 at 16:22

In addition to mockImplementation approach mentioned by @marcw (link) and since I used Object.create approach from the same thread (link), I was able to solve the issue by changing

global.window = Object.create(window);

to

global.window ??= Object.create(window);

score 6 · Answer 2 · answered Apr 19 '23 at 22:55

6

This was an issue in jest-canvas-mock that was fixed in 2.4.0.

Upgrading to 2.4.0 or later should resolve the issue, and allow use of node 18 or better.

answered Apr 19 '23 at 22:55

sklnd

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I can not confirm this. Got 2.4.0 and it is still an issue. – ffritz Apr 21 '23 at 07:20
I added `npm install jest-canvas-mock@latest --legacy-peer-deps` to my CI pipeline and that did fix it. – rob Apr 27 '23 at 19:35

score -4 · Answer 3 · answered Mar 02 '23 at 14:53

-4

I changed my node version from 18 to 16.10 and it fixed the problem.

answered Mar 02 '23 at 14:53

Petr

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That seems like an overreaction. – Connor Low Apr 19 '23 at 23:06
2

That is not an acceptable solution. – ffritz Apr 21 '23 at 07:19
3

Does not help at all. Nobody sane wants to downgrade. – simPod Apr 26 '23 at 18:48
3

This answer would have been handy as a comment. Downgrading does provide a step in the process of investigating an issue. But it is very rare that downgrading is the answer. – rob Apr 27 '23 at 19:37

Jest: TypeError: Cannot redefine property: window

3 Answers3