Undefined type being passed to resolveTypeArguments in certain cases

[tnrich]

Hey @thiagobustamante and whoever else maintains this! Thanks again for the awesome tool!

So.. I was generating swagger json using swaggerGen:

Here are some of the types:

import { Errors } from "typescript-rest";

export interface ErrorWithDetails<T> {
  details?: T,
}
export class ConflictErrorWithDetails<T> extends Errors.ConflictError implements ErrorWithDetails<T> {
  details?: T;
  constructor(message?: string, details?: T) {
    super(message);
    this.details = details
  }
}

I then use that here in a @Response tag:

@Response<ConflictErrorWithDetails<DuplicatesFoundResult>>(409, "Duplicate sequences detected", {
  name: "ConflictError",
  message: "Duplicate sequences detected",
  details: {
    ...etc...
  },
  statusCode: 409
})

I was getting a difficult to debug error:

There was a problem resolving type of 'ConflictErrorWithDetailsDuplicatesFoundResult'.
/Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/resolveType.js:235
        throw err;
        ^

TypeError: Cannot read property 'typeParameters' of undefined
    at buildGenericTypeMap (/Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/resolveType.js:581:14)
    at resolveTypeArguments (/Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/resolveType.js:590:18)
    at /Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/resolveType.js:516:34
    at Array.forEach (<anonymous>)
    at /Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/resolveType.js:509:22
    at Array.forEach (<anonymous>)
    at getInheritedProperties (/Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/resolveType.js:505:21)
    at getReferenceType (/Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/resolveType.js:228:34)
    at Object.resolveType (/Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/resolveType.js:76:25)
    at /Users/tnrich/Sites/lims/tg-cli-api/node_modules/typescript-rest-swagger/dist/metadata/endpointGenerator.js:117:37
    at Array.map (<anonymous>)

I dug deeper by debugging in node inspector:

As you can see in the above image, the actual issue is that type===undefined we should at the very least return a better error message when type===undefined. I'll put a PR in for that right now.

After understanding the issue better, I was able to fix it by explicitly importing:
import { ConflictError, HttpError } from "typescript-rest/dist/server/model/errors";
instead of
import { Errors } from "typescript-rest";

That can work for right now but seems like an imperfect solution (because ConflictError, HttpError aren't exposed as top level exports in typescript-rest).

It seems like the best solution would be improve the typescript-rest-swagger MetadataGenerator to properly find all the included types coming from a top-level import.

Thanks!

[tnrich]

@ngraef any thoughts on this?