Support auto-updated model properties "createdAt" and "updateAt"

Feature proposal

While creating a model/Entity from cli, I have an option to create a date field. A common example would be a user model with created_at and updated_at fields (or any variants of createdAt and updatedAt). Typically the behaviour is that on new resource creation, I would like to set the created_at and updated_at as the current time. on subsequent updates, I would like to update the updated_at timestamp with the time of operation.

Given that created_at needs to be populated at creation and updated_at needs to be updated with every modification, it can be a nice inbuilt feature to have with models where I can say that a particular field acts as created_at and another one as updated_at and loopback can take care of updating these fields, saving me some lines of code.

Commencez par retracer le chemin de création de model/Entity exposé via la CLI et la manière dont les propriétés du modèle sont gérées lors de la création et des mises à jour des ressources. Confirmez la configuration prévue pour les variantes createdAt et updatedAt, puis définissez des tests montrant que la création définit les deux horodatages et que les modifications ultérieures mettent à jour uniquement l’horodatage de modification.