Mocking window not working on Node >= 7.3

[alexjoverm]

Bug
I've been using the following code for mocking the window (in TS, but should be the same for js). It used to work:

interface MockWindow extends Window {
  addEventListener: jest.Mock<{}> & typeof window.addEventListener
  removeEventListener: jest.Mock<{}> & typeof window.removeEventListener
}
function getMockWindow() {
  window.addEventListener = jest.fn()
  window.removeEventListener = jest.fn()
  return window as MockWindow
}
let mockWindow = getMockWindow()

But now is not mocking the window correctly. So cannot check calls or call mockClear and that stuff:

mockWindow.addEventListener.mockClear() // doesn't find the method

Curiously, it was happening in my TravisCI as well, but I stop caching node_modules (I was doing it) and now works again. But still locally I having that issue. Any clue?

You could reproduce it like this

git clone https://github.com/coosto/ShortcutJS
yarn install
yarn run test -- --no-cache

Please provide your exact Jest configuration and mention your Jest, node, yarn/npm version and operating system.

• Windows 10
• jest 18.1.0
• yarn 0.18.1
• npm 4.0.5
• node 7.4.0

[alexjoverm]

Ok, new info -> in Node <= 7.2 works. Node > 7.2 fails.... Is there some known incompatibility issues?

[thymikee]

Maybe it's some kind of regression in Node, but nothing I've heard before.

[alexjoverm]

Ok, new info again... This is crazy.

• Node <= 7.2: works
• Node 7.3, 7.4: doesn't work
• Node 7.5: works again

WTF?

[alexjoverm]

P.D.: perhaps we could close it, still I'm very curious about the issue

[alexjoverm]

Ok, confirmed. I've just found @cpojer opened an issue and there is a regression in Node 7.3 (fixed by 7.5) that breaks some things nodejs/node#10492

This should be communicated somewhere in the docs, right? cc @thymikee

[cpojer]

Yup, that's a node issue. Let's look past this and never speak of Node 7.3 and Node 7.4 again.

[github-actions]

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