Can someone show me an example of how to write a custom decorator?

[dsmurl]

I'm reading that this seems to be the only way to add a little business logic to the resolvers without messing with them before generation.

[MichalLytek]

https://typegraphql.com/docs/custom-decorators.html

[dsmurl]

Thanks, this is epic. Just as a followup, I used that in combination with the typegraphql-prisma instructions here:

https://prisma.typegraphql.com/docs/advanced/additional-decorators

to make a call like 'applyResolversEnhanceMap(resolversEnhanceMap);' before the buildSchema and it did the trick. Then I passed in a connected PrismaClient to the decorator function to check stuff within the ORM models like my Issues here:

import {
  ClassType,
  ArgumentValidationError,
  createMethodDecorator,
} from "type-graphql";
import { PrismaClient } from "@prisma/client";

// sample implementation of custom validation decorator
// this example use `class-validator` however you can plug-in `joi` or any other lib
export function ValidateDeleteIssueOwnership<T extends object>(
  Type: ClassType<T>,
  prisma: PrismaClient
) {
  return createMethodDecorator(async ({ args, context, info }, next) => {
    const instance = Object.assign(new Type(), args);
    console.log(" instance: ", instance);

    // console.log(' context: ', context);
    // console.log(' info: ', info);

    // const validationErrors = await validate(instance);
    // if (validationErrors.length > 0) {
    //   throw new ArgumentValidationError(validationErrors);
    // }

    const numberIssues = await prisma.issue.count();
    if (numberIssues === 0) {
      throw new Error(
        "CUSTOM DECORATOR - Oh Nos!!!  There were no issues to delete!  "
      );
    }

    return next();
  });
}