Support some way of annotating that some fields should not be removed from data model even though the component is hidden

[ivarne]

Description

A layout can define some components as conditionally "hidden" with an expression. If the user enters some information in a component before changing (a presumably earlier) answer, so that a components "hidden" expression changes value, it usually makes sense to remove the associated data. Because users might explore the logic of the app, the data needs to show up if he reverts the choice that triggered the condition.

Removal of data is done in 3 cases

• appLogic.RemoveHiddenData adds a step when finishing a task to remove all hidden fields from the data model(s)
• Validators that implement ShouldRunAfterRemovingHiddenData => true will not see hidden fields
• DataProcessors that uses dataMutator.GetCleanDataAccessor().GetFormData<Model>()

Sometimes we want to hide components in the frontend, without actually removing the data. There are multiple ways to implement this, and we need to make the right choice.

There are 4 distinct outcomes that are possible

1. Field is not hidden and not removed
2. Field is hidden and removed
3. Field is hidden but not removed
4. Field is not hidden but removed (maybe not relevant?)

As we have 1 boolean expression "hidden", it makes sense to expand to 4 options by adding another boolean option.

1. New expression property "remove" on component

The most obvious solution would be to add a new expression "remove", but for backwards compatibility it needs to default to the current value of "hidden" if undefined or null.

Is it obvious what "remove" would mean?

2. New property "removeWhenHidden" on component

This does not support outcome 4, and it is slightly awkward that the default will depend on appSettings.RemoveHiddenData, so we have a 3 way boolean
It has a few nice properties.

• Mostly not needed
• Adds a path to remove the global setting RemoveHiddenData, because we can set removeWhenHidden to false on all fields in a upgrade script.

3. New property "visuallyHidden" on component

For visual representations (frontend) it is evaluated and or'ed with "hidden", but when removing data it is ignored.

Other alternatives (better naming)

???

[rvessb]

Jeg lurer på om det hadde vært en ide å opprettet en setting i selve datamodellen som sier noe on variabelen skal kunne slettes ved innsending....?
Ved å ha dette på komponeten (som du drodler rundt her), så får man fort situasjonen at man kan ha motstridende setting på forskjellige komponenter som peker mot samme felt i datamodellen.
Dessuten kan det være felt i repeterende datastrukturer (typisk prefill) som vi ikke ønsker at skal slettes selv om raden ved innsending var skjult. Dette er typisk data som aldri er knyttet til en komponent, eller den brukes bare i en "visningskomponent". Men dataene vil pr i dag slettes hvis raden de lever i ( i datamodellen) er skjult.
Den siste her er viktig å ivareta da vi ønsker at de som oppretter "kopi fra arkiv" skal ha all opprinnelig prefill inntakt.