Is it possible for one property in a model to re-use the value of another?

[wrex]

I'm writing some tests and would like to model a REST API out of my control. GET requests to that API return JSON objects like:

{
  "id": 534342,
  "object": "review",
  "url": "https://api.wanikani.com/v2/reviews/534342",
  "data_updated_at": "2017-12-20T01:00:59.255427Z",
  "data": {
    "created_at": "2017-12-20T01:00:59.255427Z",
    ...
  }
}

The URL value always includes the ID value, which is redundant and not normalized but I'd like to model it nonetheless.

Is there a reliable and idiomatic way for a factory to return two properties with the same value within both? I'd like to use the moral equivalent of this.id in the parameters to the factory, but I'm unsure how to go about it. Something like the following:

const db = factory({
  user: {
    id: primaryKey(() => datatype.number({max: 999999})),
    url: () => `https://api.wanikani.com/v2/reviews/{this.id}`,  // doesn't work, of course
    ...
  },
})

Thanks in advance!

[kettanaito]

Hey, @wrex. Thank you for raising this!

Currently, we don't have an API to allow referencing other properties of the same entity in the value getters. There's, however, a suggestion in #95. We would like to support this, so please share with us any ideas/suggestions on how you want this API to work in the said issue.

Ideally, I'd like to see an API like this:

factory({
  user: {
    id: primaryKey(...),
    url: (entity) => entity.id
  }
})

[wrex]

Yes, passing the current entity as a parameter would work great for my simple use-case. I'll redirect further comments to issue #95.

Also: Thanks for this useful library! It's proving very useful to me even outside of an msw context (where I'm mocking a higher level client-side library that takes care of caching and pagination with the server-side API).

[kettanaito]

I would be grateful for your input!

Thank you for your kind words. With Data we strive to design a standalone tool in the first place, ensure smooth integration with MSW as a nice feature later. Please, if you would like for this library to improve, consider supporting our team at Open Collective. Any contribution counts.