Add nickname autofilling to the sign up form

Is your feature request related to a problem? Please describe.
Our clients report that many of their users do not understand the difference between name and nickname when they sign up :

• some don’t know what to input (it can be creative out of the blue ;))
• some feel like they are asked to input the same info twice and find it annoying
• some will create errors by inputing special characters* or going over the limit (25)
• Constraint not mentioned in a help text that the user discovers with an error message after sending the form

This creates unnecessary frictions at a crucial step.

Describe the solution you'd like
In order to make it easier to sign up on Decidim, we propose

• to automatically fill the user nickname field using the name input
• hide the nickname field on the signup form to avoid any confusion*

*(what is this second field ? why is it autofilled ?) + they can always change it later in their account settings

We propose to generate the nickname in the following way :

• delete spaces
• no uppercase
• delete special characters
• 25 characters
• when duplacate add a number that can be incremented
• keep 2 characters for numbers at the end

Example :

Name : Constantin Guillaume de La villardière → Nickname : constantinguillaumedela

If a other users register with the same name we’ll have :

constantinguillaumedela1

constantinguillaumedela2

.

.

constantinguillaumedela99

Describe alternatives you've considered
-

Additional context
This was tried by Platoniq on one of their instance, they told us it really helped with registration.

This proposal is part of a larger scope to improve authentication flow in Decidim. Working document here (External link).

Does this issue could impact on users private data?
No

Funded by
OSP and Angers