Simplify Nested model forms with Phoenix LiveView

[rockwood]

Thanks for the great article!

I just wanted to give some feedback after implementing my own solution.

I believe the things can be simplified by utilizing the :ignore action on the variant changeset when no id exists.

defp maybe_mark_for_deletion(changeset) do
  if get_change(changeset, :delete) do
    %{changeset | action: (if changeset.data.id, do: :delete, else: :ignore)}
  else
    changeset
  end
end

This way, the temp_id virtual attribute and the remove-variant action can be removed entirely. The same deletion logic would apply to both new and existing records.

[inoas]

The other thing to note is that I had quite some buggy behavior in live view until I changed

%{changeset | action: :delete} to: put_change(changeset, :action, :delete)

Edit: nope, the reason was that I missed :action in cast() in the variant schema :/.

Edit 2, this is what I run:

  defp maybe_mark_for_deletion(changeset) do
    if get_change(changeset, :delete) do
      # %{changeset | action: if(changeset.data.id, do: :delete, else: :ignore)}
      changeset |> put_change(:action, if(changeset.data.id, do: :delete, else: :ignore))
    else
      changeset
    end
  end