Display an error in case the map is saved without a connexion

[davidbgk]

Describe the bug

At the moment, no error is returned in case the Save button is clicked while the user is offline.

Expected behavior

We want to display a feedback for the user.

[yohanboniface]

Can't we detect the network status before and grey/deactivate the save button ?

[davidbgk]

It would mean we poll constantly?

[yohanboniface]

Dunno :p How they do in hackmd or this kind of apps ? Websockets ?

[davidbgk]

Maybe one day https://developer.mozilla.org/en-US/docs/Web/API/NetworkInformation