Checkbox component should support mapping to an array

[lorang92]

Description

The current implementation of the checkbox component maps answers to a comma-separated string. As an app developer, it feels more natural that these values are mapped as an array. We should support both cases 🦅 and make this setting configurable on the component.

Considerations

• Default config? We have to stick to the current implementation as default as this could break existing apps. (or if we strongly belive that an array is better we should create a new major versjon.)
• Adding a checkbox-component from studio could potentially be setup as array mapping as default for all new boxes

Depends on #345 to be solved first.

Acceptance criteria

• Checkbox component should support mapping data to an array structure
• Make this mapping configurable at the component
• Default mapping should be a comma-separated string

Specification tasks

• Development tasks are defined

Development tasks

• Implement configurable setting in formlayout.json
  • update json-schema with new possible config values
• update checkbox-component to handle both cases
• unit tests

Test

Add test cases here as checkboxes that are being tested as part of the changes.

Definition of done

Verify that this issue meets DoD (Only for project members) before closing.

• Documentation is updated (if relevant)
  • Technical documentation (docs.altinn.studio)
  • User documentation (altinn.github.io/docs)
• QA
• Manual test is complete (if relevant)
• Automated test is implemented (if relevant)
• All tasks in this userstory are closed (i.e. remaining tasks are moved to other user stories or marked obsolete)

[ivarne]

Is this actually possible as long as we convert all the datamodel fields to string in app-frontend?

[olemartinorg]

Psst! We now have backend support for scalar arrays, and the frontend includes support for the list binding for attachment references (see Altinn/altinn-studio#246). I've noticed this issue myself, and it should be fairly easy to add support for the list binding here as well.

[FinnurO]

I am sure I saw an issue where the need for checkbox mapping to datamodel fields was mentioned. It said it is a common pattern i Altinn 2.

Here it is: #789