Output arrays and instances. Requirement of input.

[Aymericr]

I get type error while declaring output from defaultEndpointsFactory build method. I couldn't find any answer in the documentation.

"typescript": "^4.7.4",
"express-zod-api": "^8.3.4",

// imports
import { Feature, FeatureService } from '@entities/feature.entity';
import { 
  createServer, 
  Routing, 
  z, 
  defaultEndpointsFactory,
  createResultHandler,
  createApiResponse,
  IOSchema,
  EndpointsFactory,
  createConfig,
} from "express-zod-api";

// code
const getFeatures = defaultEndpointsFactory.build({
  method: "get",
  output: z.any().array(),
  handler: async () => {
    const features = new FeatureService();
    const featureList = await features.list();
    return featureList;
  },
});

The type error: (property) output: z.ZodArray<z.ZodAny, "many">

Type 'ZodArray<ZodAny, "many">' is not assignable to type 'IOSchema<any>'.
  Property 'innerType' is missing in type 'ZodArray<ZodAny, "many">' but required in type 'ZodEffects<ZodObject<any, any, ZodTypeAny, { [x: string]: any; }, { [x: string]: any; }>, { [x: string]: any; }, { [x: string]: any; }>'.ts(2322)
types.d.ts(631, 5): 'innerType' is declared here.
endpoints-factory.d.ts(14, 5): The expected type comes from property 'output' which is declared here on type 'BuildProps<IOSchema<any>, IOSchema<any>, null, {}, "get", string, string>'

[Aymericr]

This will work though:

const getFeatures = defaultEndpointsFactory.build({
  method: "get",
  input: z.object({}),
  output: z.object({
    features: z.any().array(),
  }),
  handler: async () => {
    const features = new FeatureService();
    const featureList = await features.list();
    return {
      features: featureList
    };
  },
});

I would like to be able to write output: z.instanceof(Feature).array() without having to nest it under z.object({...})

Another weird behavior: why input is required for a "get" method?

[RobinTail]

Hello @Aymericr .

Thank you for reaching out.

Regarding arrays

This is not a bug, it's intentionally made that way to encourage developers to always operate objects, as a best practice, since objects can evolve preserving the backward compatibility.
However, if you still want for some reason to respond with an array, you'd need to make a custom ResultHandler.
Find out more here:
#361
Long story short: your endpoint still have to output an object, but your custom ResultHandler may pick a certain field containing the array and respond with it.

Regarding instanses

I would like to be able to write output: z.instanceof(Feature).array()

Currently this is not possible, since z.instanceOf() means an instance of a class. Classes have to be serialized to something compatible for HTTP transfer (read: JSON-compatible), so in order to avoid uncertainty on the way of serialization, the library does not support usage of z.instanceOf in I/O (at least currently). You need to define the schema of the class serialization and do that serialization in the endpoint handler.

Regarding inputs

Another weird behavior: why input is required for a "get" method?

If your endpoint does not have any inputs, you need to write input: z.object({}), this is required (at least currently) since input is always an object produced by the combination of request properties (such as body, query and params).
But I agree, that this could be made optional as the future improvement to imply empty object as the default input schema.

I hope I managed to answer all your questions.
Please let me know if something is not clear yet.

[RobinTail]

Now supporting array response: #361 (comment)
(at your own risk)