React-final-form: Uncaught TypeError: Cannot read property 'subscription' of undefined when using FormSpy

Created on 13 Feb 2018 · 10Comments · Source: final-form/react-final-form

Are you submitting a bug report or a feature request?

Bug report

What is the current behavior?

When rendering a Form with a FormSpy, it becomes impossible to remove the spy from the react hierarchy based on form state, without triggering errors during subscription handling.

In the sandbox example, submitting the form will trigger the form to re-render and only return a string, unmounting the FormSpy. This will then lead to an error being thrown.

A workaround is to keep rendering the FormSpy regardless of whether the form has been successfully submitted.

What is the expected behavior?

It should be possible to remove the FormSpy from the tree without having it conflict with subscription handling.

Sandbox Link

https://codesandbox.io/s/0o6o6mp3ov

What's your environment?

final-form 4.2.0
react-final-form 3.1.0

Source

johanneslumpe

👍4

Most helpful comment

Published fix in [email protected].

erikras on 16 May 2019

🎉2

All 10 comments

Is there any news regarding this bug?

vasilich6107 on 12 Sep 2018

I'm trying to reproduce it.

maciejmyslinski on 17 Sep 2018

reproduced, let me debug it.

maciejmyslinski on 17 Sep 2018

Updating the FF and RFF deps in that code sandbox fixes the problem. 🤷‍♂️

erikras on 19 Sep 2018

👍1

I still have this issue with updated dependencies

Uncaught (in promise) TypeError: Cannot read property 'subscription' of undefined
    at final-form.es.js:382
    at Array.forEach (<anonymous>)
    at notify (final-form.es.js:380)
    at notifyFormListeners (final-form.es.js:798)
    at complete (final-form.es.js:1132)

mschipperheyn on 31 Dec 2018

👍2

Just found the same error (version 4.12.0)

final-form.es.js:407 Uncaught (in promise) TypeError: Cannot read property 'subscription' of undefined
    at final-form.es.js:407
    at Array.forEach (<anonymous>)
    at notify (final-form.es.js:405)
    at notifyFormListeners (final-form.es.js:827)
    at complete (final-form.es.js:1182)

stefanoferretti on 13 Mar 2019

👍1

For what it's worth, it is also happening with final-form 4.11.1 and react-final-form 4.0.2.
I am unsure what are the conditions to replicate it. I will post more information when I identify what conditions trigger this error.