graphql with typescript - @FieldResolver not working in compiled-to-js type-graphql

0
votes

I a newbie with type-graphql and I have this weird issue of field resolvers not working.

I'm using a stack of:

  • typescript(3.9.5)
  • type-graphql(1.0.0)
  • typeorm(0.2.25)
  • apollo(2.16.0).

Whenever I run my typescript (using ts-node) everything works well, but when I use the compiled js version with express, the queries work only with simple db fields, but fieldResolvers don't work at all and in the end I get "Cannot return null for non-nullable field". The funny thing is that the field resolvers are sibling of query resolvers in the same @Resolver class. the queries get fired (placed a console log) but the field resolvers never do. anyone have a clue?

here are some snippets from the code:

@Entity()
@ObjectType()
export class Member extends BaseEntity {
  @Field(() => ID)
  @PrimaryGeneratedColumn()
  id: string;

  @UseForSearch()
  @UseAsTitle()
  @Field(() => String)
  @IsEmail()
  @Column({ type: 'varchar', unique: true })
  email: string;

  @Field(() => [Item])
  @OneToMany(type => Item, item => item.member)
  items?: Item[];

  @OneToMany(type => Review, review => review.member)
  reviews?: Review[];

  @Field(() => Number)
  itemsCount: number;
}


@Entity()
@ObjectType()
export class Item extends BaseEntity {
  @Field(() => ID)
  @PrimaryGeneratedColumn()
  id: string;

  @ManyToOne(type => Category, category => category.items)
  @JoinColumn({ name: 'categoryId' })
  @Field(() => Category)
  category?: Category;

  @Field(() => String, { nullable: true })
  @Column({
    nullable: true,
  })
  name: string;

  @ManyToOne(type => Member, member => member.items)
  @JoinColumn({ name: 'memberId' })
  @Field(() => Member)
  member?: Member;

  @Field(() => ID)
  @Column('int', { nullable: true })
  public memberId: number | null;
}

import { Resolver, Query, FieldResolver, Root, Ctx, Arg } from 'type-graphql';
import { getRepository, Repository } from 'typeorm';
import { Item } from '../entity';
import { Member } from '../entity/member';

@Resolver(of => Member)
export class MemberResolver {
  constructor(private itemsRepository: Repository<Item>) {
    this.itemsRepository = getRepository(Item);
  }

  @Query(() => [Member])
  members() {
    console.log('in members query');
    return Member.find();
  }

  @FieldResolver()
  async items(@Root() member: Member) {
    return await this.itemsRepository.find({ where: { memberId: member.id } });
  }

  @FieldResolver()
  async itemsCount(@Root() member: Member) {
    console.log('in itemsCount resolver');
    return this.itemsRepository.count({ where: { memberId: member.id } });
  }


query {
  members {
    email
    itemsCount
  }
}

{
  "errors": [
    {
      "message": "Cannot return null for non-nullable field Member.itemsCount.",
      "locations": [
        {
          "line": 4,
          "column": 5
        }
      ],
      "path": [
        "members",
        0,
        "itemsCount"
      ],
      "extensions": {
        "code": "INTERNAL_SERVER_ERROR",
        "exception": {
          "stacktrace": [
            "Error: Cannot return null for non-nullable field Member.itemsCount.",
            "    at completeValue (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:599:13)",
            "    at completeValueCatchingError (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:534:19)",
            "    at resolveField (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:465:10)",
            "    at executeFields (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:297:18)",
            "    at collectAndExecuteSubfields (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:752:10)",
            "    at completeObjectValue (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:742:10)",
            "    at completeValue (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:630:12)",
            "    at completeValue (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:596:21)",
            "    at completeValueCatchingError (/Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:534:19)",
            "    at /Users/admin/tackar/clampa/clampa-server/node_modules/graphql/execution/execute.js:655:25"
          ]
        }
      }
    }
  ],
  "data": null
}
2
graphqltypeormtypegraphql

2 Answers

0
votes

There is an issue with your compile step (TS to JS) - if it doesn't emit ES6 classes and arrow functions, it will treat of => Member as a function with prototype, so it gonna think it's the object type class.

0
votes

The problem is not the compiling. The problem is your data

the message you are seeing is Cannot return null for non-nullable field Member.itemsCount

Well, either you add a value in itemsCount, or mark the field as nullable. And the problem is you are missing an await before the call to members count

Just add the await

 @FieldResolver()
  async itemsCount(@Root() member: Member) {
    console.log('in itemsCount resolver');
    return await this.itemsRepository.count({ where: { memberId: member.id } });
  }