[MU] Save draft locally periodically

[chibenwa]

Description

On WEB:

GIVEN I type a message
AND stop typing for 15 seconds
THEN twake mail saves the email locally (not on the JMAP server)

That way if the broswer crash (eg power failure) then the email is not lost.

When reopening the browser the composer should be reopened with user input.

Ref: https://github.com/Yash18-hub/CISD-GES/issues/88

Let's not save on the back as it might create a massive surge in requests

[tddang-linagora]

Ref: https://github.com/Yash18-hub/CISD-GES/issues/88

404

[tddang-linagora]

1. User is composing email, cache timer (in this case, 15s) is already due and the cache is saved
2. Browser crashes/Laptop dies/User force-quit browser, cache is already set so no problem
3. When user reopen app, check cache storage to see if there's any entry. If yes, show a dialog to let user choose what's going to happen next

• Discard
• Save to draft (server side)*
• Continue to edit

Is this the desired behavior?
What if * failed, then user proceed to compose another email, and 1, 2, 3 happens. There will be more than 1 cache entry now. What happen then when user reopen the app?

[chibenwa]

Yes it looks like a nice behaviour

[tddang-linagora]

How about the second question? What if there are multiple cache entries?

[tddang-linagora]

Note:

• If browser has multiple cache entries, get the latest cache first, then if that cache is handled, get the next one everytime user open the app until there is no more cache entry left.

[tddang-linagora]

#3372 (comment)

[chibenwa]

Implemented with local cache