onChange fired on mount and unmount

[mattcorner]

Bug Report

Describe the bug

As of 3.0.0, the onChange method is fired on dropzone component mount, and also unmount with empty files array. This is undesirable.

Steps to reproduce

Code sandbox demo
Note alert on page load. Note alert on toggling dropzone off so that it is unmounted.

Expected behavior

No callback trigger on mount and unmount. I should only expect an onChange with empty files when a user has removed a file from dropzone.

Versions

• OS: windows
• Browser: chrome, edge
• @material-ui/core version: latest
• material-ui-dropzone version: 3.0.0

Additional context

[mattcorner]

Just found the clearOnUnmount option which give me the unmount behaviour I expect. Wonder why I never got unmount callback triggers in 2.x.x. I guess the bug is there rather than 3.0.0

[BGehrels]

Sadly, this one got closed.

I would definitly love some documentation about this behaviour in the breaking changes section of the release notes.

[panz3r]

Hi @mattcorner and @BGehrels ,

Thanks for your feedbacks.

I updated the CHANGELOG to better explain the change about onChange behaviour, also to clarify the main reason behind this change is because of a better handling of the initialFiles prop on mount, the event is also triggered on unmount when the clearOnUnmount prop is set to true.