[Feat] Change `computedFields` to `compute` function that returns an `Object`

[cangSDARM]

because sometimes more content is needed to generate

like:

 computedFields: {
    extra_info: {
      type: "json",
      resolve: (post) => {
        const url = post._raw.flattenedPath;
        const [collection, ...slug] = url.split("/");

        return { collection, slug, url };
      },
    },
 },

into:

 compute: (post) =>{
    return {
      type: "json",
      resolve: (post) => {
        const url = post._raw.flattenedPath;
        const [collection, ...slug] = url.split("/");

        return { collection, slug, url };
      },
    };
 },

with function, it can be simpler.

[schickling]

Thanks a lot for opening this issue. I like this API design idea in general however we'd need to figure out a way to either automatically derive or let the user specify the return type (schema) of the compute function. Any ideas?

[cangSDARM]

How about passing an option parameter? Can the user call something like option.defineSchema('schema')?

 compute: (post, option) =>{
       const url = post._raw.flattenedPath;
       const [collection, ...slug] = url.split("/");
   
       option.defineSchema({
          collection: 'string',
          slug: 'string[]',
          url: 'string'
       });

       return { collection, slug, url };
 },

Or does the underlying internal use Object.getOwnProperties(returned) to iterate over all the properties to generate those types?