Filter/Where as a standalone concept

Refactor the current implementation of LoopBack's Filter to allow other packages to leverage the filtering implementation and/or support LoopBack's Filter syntax.

1. The syntax of Filter/Where objects should be well defined and properly documented, to allow 3rd-party implementations to understand all possible values.

2. There should be TypeScript typings describing Filter, Where, etc., these typings must be accessible independently on @loopback/repository (e.g. via a new package).

3. The implementation used by our memory connector should be refactored/extracted into a package that can be used independently from juggler (something like https://www.npmjs.com/package/loopback-filters). It's important to update the connector to use that new package, to ensure there is only single reference implementation.

Nice to have:

• JSON Schema describing Filter syntax
• Some sort of a test suite to allow 3rd-party implementations to verify conformance

Commencez par localiser l’implémentation existante de Filter/Where de LoopBack et le connecteur mémoire dans juggler, puis examinez comment @loopback/repository expose ses types. Le travail est considéré comme terminé lorsque la syntaxe est documentée, que des définitions de types TypeScript indépendantes et un package de filtrage réutilisable existent, que le connecteur mémoire utilise l’implémentation partagée et que les tests proposés de JSON Schema ou de conformité sont pris en compte.