Lots of dynamic notification banners when I invite a couple people on the doc

[virgile-dev]

Feature Request

Is your feature request related to a problem or unsupported use case? Please describe.
If I invite a few people on the doc, one notification banner appears for each user. Which is annoying

Describe the solution you'd like
Can we make a single notification for the whole group or just change the UX.
Or better if invitations went through, just close the pane and notify me if there is an error.

[PanchoutNathan]

It has to come from the back first. Because it is impossible to add several members at once, we have to do a foreach. I think this is a pretty bad practice for several reasons. Like error handling or performance too. @sampaccoud @AntoLC

[AntoLC]

I think you can, when all the promises are made, we foreach them to show our toast popup, see:
https://github.com/numerique-gouv/impress/blob/1d1832b67a2453fefb298c9faad926f7c6865599/src/frontend/apps/impress/src/features/docs/members/members-add/components/AddMembers.tsx#L137-L148

I think we should keep this mechanism for onError, it is nice to know with which member the endpoint failed, but when it is successful, to show only 1 toast is probably enough, moreover they are listed in real time in your member list.

[PanchoutNathan]

Yes, it is clearly possible on the front side not to display several toasts. But I find it a shame to do so many "tricks" when it would be enough for the back to accept a batch of members to be added in a single POST.

Because regarding performance or even simpler error management (because in the case where there are lots of errors, it amounts to displaying n toasts, or if we only display one error toast, we will not have the detail, except by tinkering)

But if you have to do the front version, no problem.

[virgile-dev]

With @rl-83 we worked on a revamp of the notifications.
Could you detail here what we discussed and and link to the designs ?

[robin-lecomte]

Description

This feature has been designed as part of the Subpages Update.

• Alerts appear at the bottom of the screen, in the center. They last for 5 seconds and then disappear permanently.
• A new alert takes the place of the old one (if another action is performed within 5 seconds). They do not stack.
• Alerts do not appear on mobile to avoid overloading the interface.
• Cases retained:
  a. Confirmation of link copied to the clipboard
  b. Confirmation of move to the trash, with the possibility of going back
  c. Error uploading a video or file.
• The confirmation of title change for a document is removed.

Reference prototype on Figma (FR)