Custom Types have wrong `_type` key

Let’s have the following simple schemas:

const fooImage = {
  type: 'image',
  title: 'Top-level Image Type',
  name: 'foo_image',
  fields: [
    {
      title: 'Title',
      name: 'title',
      type: 'string',
    },
  ],
};

const bar = {
  type: 'document',
  title: 'Bar',
  name: 'bar',
  fields: [
    {
      title: 'Nested Image Type',
      name: 'nestedImage',
      type: 'foo_image',
    }
  ],
};

When generated, the FooImage type is outputted like so:

export type FooImage = {
  _type: "image";
  asset: SanityAsset;
  /**
   * Title — `string`
   *
   *
   */
  title?: string;
};

However, the _type property is wrongly represented, as the _type of it should in fact be foo_image when referenced from the Bar document.

I don’t see any use case requiring to have the “base type” present in the _type property, but I may be wrong. Having the custom type there would better represent the actual Sanity API response format.

[ricokahler]

I merged a fix that should fix it for images and files but I think slug is still an issue. I’ll address in a separate PR once I get some time.

[alexbchr]

Great! I took a quick try at it sooner today and it proved to be maybe more complex to do that what I initially thought. Unfortunately, I don’t have enough time today to dig more into it.

Just to add to the example, it is not only image which is problematic. This should be the behavior for all Types (image, file, slug, object and so on…). I did a very quick fix this morning (only for image and file types), here is the code (quite incomplete and a test still, but feel free to use it).