'Cannot read properties of undefined (reading 'url')' when multiple browser tabs are open

[vik-buchinski]

Prerequisites

• [X] I confirm my issue is not in the opened issues
• [X] I confirm the Frequently Asked Questions didn't contain the answer to my issue

Environment check

• [X] I'm using the latest msw version
• [X] I'm using Node.js version 18 or higher

Browsers

Chromium (Chrome, Brave, etc.)

Reproduction repository

https://github.com/hal-shin/msw-bug

Reproduction steps

1. install nodejs v20.12.2
2. npm i
3. npm start
4. open 2 tabs 'http://localhost:3000/'
5. after opening the second tab, you'll see the following error:

Current behavior

when the second tab opened, I see 'Cannot read properties of undefined (reading 'url')' error.

Affected versions: >2.1.7 Versions that work correctly: <= 2.1.7

Expected behavior

application should continue working when it is opened in 2 tabs.

[akumapps]

Same behavior here with version 2.3.0

[kaique64]

I got the same behavior here with version 2.3.0

[gypz24]

I got the same result

[ByteWither]

@kettanaito Hi! I find this PR #2031. I think it is a reason of this bug. Can you fix it? Also, I still get error with version 2.3.1 :(

[PedroBarbosaSw]

Any update regarding this issue?

[Crauzer]

This is also happening on the latest version 2.4.11, when multiple tabs of the same origin are open, this error shows up once for each open tab.

The service worker also crashes when you reload the page multiple times:

[Marcosld]

We are having this problem in our project. It breaks our screenshot/acceptance tests :(

[diego-aquino]

I can confirm that this issue is still happening in msw@2.5.1, using the same reproduction created by @vik-buchinski.

---

It looks like request is getting undefined and line 58 throws:

https://github.com/mswjs/msw/blob/9dc2d71199021c62ad8926555c0313d3b1bd6995/src/browser/setupWorker/start/createResponseListener.ts#L56-L61

request comes from a map and in fact can be undefined, but the code uses a non-null assertion (!).

https://github.com/mswjs/msw/blob/9dc2d71199021c62ad8926555c0313d3b1bd6995/src/browser/setupWorker/start/createResponseListener.ts#L21

I have no deep knowledge of this function, but maybe msw needs to check if request exists before using it?

[NullVoxPopuli]

Present in 2.6.2 as well

[rkambara]

2.6.4 as well

[artsiomshushkevich]

Hi msw v2.6.5 also has this issue but in a different place. Please have a look