How to migrate model mixins #3951
Description
This is a follow-up for #3718 and #3922.
Write content for docs/site/migration/models/mixins.md, explain how to migrate mixins from LB3 style (see Mixins docs) to LB4 style (ES2015 mixin classes).
Important: In LB3, a model class provided both Schema definition, Persistence behavior and Public API. As a result, a single LB3 mixin can contribute to all three layers. In LB4, each of these layers map to a different concept (Model class, Repository class, Controller class).
Acceptance criteria
Migration guide describing how to:
- Convert a LB3 "mixin function" to LB4 mixin class factory
- Migrate mixins contributing to model schema (e.g. new property definitions)
- Migrate mixins modifying persistence behavior (e.g. adding new methods, installing operation hooks, etc.)
- Migrate mixins modifying API (e.g. adding new public methods, modifying remoting metadata of built-in LB3 methods).
- Migrate mixin configuration in LB3 model definition to LB4 Model and/or Repository.
UPDATED 2020-02-27 by @bajtos: Based on discussion with @emonddr, we decided to removed the following entry, because "mixin model" approach is not documented in LB3:
- Convert a LB3 "mixin model" to LB4 mixin class factory