Allow additional properties in model as in loopback 3

[therougeb]

Hello,

I'm migrating a project from loopback 3 to loopback 4 but i'm stuck at a feature of loopback 3 that is not kept in loopback 4.
it's very frustrating because it was very convenient in loopback 3 too add dynamic properties to the model and send back to the client the model with these additional properties.
actually it seems not possible. but for some use cases this is needed because we can 't store in database theses properties as they are dynamic, but they are not kept at runtime when added.

if somebody has a tip or possibility to add this feature it would be great.

Thanks