Nullable belongsTo relationships

[waffleau]

Why this feature is required (specific use-cases will be appreciated)?

In our table design, we sometimes have a nullable foreign key relationship with another table. In our models we then define this relationship with belongsTo. However, there does not seem to be any way to define the relationship as optional/nullable. While this isn't a breaking problem, it means downstream we can't rely on TypeScript to give us correct warnings where our relationship may be null.

As an example, if you had a model Issue, you might have a column on that table for assigneeId which is the user who is looking into the issue. While the issue is unassigned the assignee relationship is null, so we should be writing code like issue.assignee?.name. As the relationship isn't nullable however, TypeScript does not know that assignee can be null, so it will not warn us if we do not do this safely.

Similarly, it would also make sense to allow HasOne to be nullable.

Have you tried any other work arounds?

I can't find anything in the docs suggesting this is possible. I've tried some variations on the relationship definition but they don't work:

@belongsTo(() => User | null)
public user: BelongsTo<typeof User | null> = null

Are you willing to work on it with little guidance?

Yes.

[ndianabasi]

This will be a great improvement to the typings for Lucid relations.

[thetutlage]

Agree, it will be nice to allow one to one relationships to be represented as null as well. Can you open a PR for the same?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[RomainLanz]

Closing in favor of the PR.

[RomainLanz]

Relased as 18.4.1

[Marian0]

hey @waffleau

Was this resolved in the 18.4.1 ?

I'm also wondering if you experience this behavior with preloads described here: #973

It may be related.

Thanks