Reset uploader component

[tpcgold]

Describe the bug
Currently MESOP Uploader component cannot be reloaded / refreshed / reset
https://google.github.io/mesop/components/uploader/

To Reproduce
Upload a file with the uploader component and you fill get the "file name" beside the upload button.
But if one is implementing a "clear" button (e.g. in a chat) it is not possible to remove the "file name" text after the uploader button.

Expected behavior
Add a clear / refresh feature for the component

Screenshots
Before:

After pressing clear (this removes UploadedFile from state) but the uploader component (file name) cannot be "reset" and still shows the demo-image1.png

[richard-to]

Thanks for bringing this up. I've noticed this too. I'll take a look this week. Seems like it should be fixable, but if not I think this could work: https://google.github.io/mesop/components/?h=reset#resetting-a-component as a temporary workaround.

[richard-to]

Here are a few options (no particular order) API-wise:

1. Add a clear parameter. Then when cleared, send an on_clear event back to the server so that the clear parameter can be disabled. Needing to include on_clear hook to reset seems a bit tedious though

2. Add a filename parameter. If set to empty string, then the value will be cleared. If set, then the given filename will be displayed.

3. Just use the reset component use the key update workaround above.

I think I'm going to go with option 2. This way, a user can upload a file and no filename will show at all (if that's what they want). This works for now since the upload is immediate. No need to select a file and press an upload button. The main drawback with number 2 is if a user sets a filename even though nothing has been uploaded. But I think that is OK.

[richard-to]

Sorry for the delay on this. Thought I could get to it before I went OOO for a week. Unfortunately did not get to it.

My solution for this ended up being to remove the labels altogether. I realized they were a bit redundant and could be added manually in Mesop anyway which would give more flexibility.