@Before and @After hooks

Let's say we want to send informations about useage of some field of our graphql api to analitycs server. We could achieve that with:

import { ObjectType, Field, After } from 'typegql';

@ObjectType()
class Person {
  @Field() id: number;

  @Field()
  @After(() => {
    loggingService.sendLog(`User was removed`);
  })
  remove(): boolean {
    const isDeleted = userService.removeById(this.id);
    return isDeleted;
  }
}

Using resolver informations inside hook function

Arguments passed to resolver are exactly the same, as ones passed to native graphql resolver funtion. Signature of hook function is

(source, arguments, context, info) => void

In case, we'd like to add id of removed user to logs, we'd change our code to:

@ObjectType()
class Person {
  @Field() id: number;

  @Field()
  @After(user => {
    loggingService.sendLog(`User with id ${user.id} was removed`);
    // note we could as well use `this` keyword like:
    // loggingService.sendLog(`User with id ${this.id} was removed`);
  })
  remove(): boolean {
    const isDeleted = userService.removeById(this.id);
    return isDeleted;
  }
}

Notes

• If one field has many hooks of the same type - they're executed in parallel.
• Field resolver is not called until all @Before hooks are resolved