Feature Request - previousData

[DaddyWarbucks]

I love what you guys are doing here! I have often used these classes without actually integrating them into a feathers app. So I think this is a great idea.

Many of these classes do some initial lookup for their mutative methods. For example, https://github.com/wingshq/wings/blob/b991db0307e0ea08b7de29fe884b86018f9284ee/packages/knex/src/index.ts#L289
I have many instances where I am looking up the current record in order to do validation, side effects, etc.

const previousData = async (context) => {
  context.params.previousData = await service._get(context.id, context.params);
  return context;
}

Later hooks (both before and after) then use context.params.previousData to do all kinds of stuff. I have always wanted to be able to pass that param to the service method and skip its lookup.

// Knex update method
const oldData = params.previousData || await this.get(id, params)

There are some concerns when using the multi option. And there are also some concerns with whether the user passes the properly shaped previousData.

Any thoughts?

[daffl]

Thanks! I think this will be a good move forward because it'll hopefully also help to decouple Feathers services and database access. We could definitely clean up a few things when you don't have to concern yourself with external access.

I think the question here would be how previous data should behave across all instances. Not all databases require the previous data to e.g. do a patch (which seems to be much more commonly used than update).

[DaddyWarbucks]

That makes sense. I know there have been some discussions about fast/bulk patches as well, which would affect this concept. This is just something I have always noticed in most adapters and thought this was a good place to document it.

Another solution may be to handle it in _findOrGet.

async _findOrGet(id: NullableAdapterId, params?: Params) {
  if (params.previousData) {
    return params.previousData;
  }
  return id === null ? await this.find(params) : await this.get(id, params)
}