Nest Error: Cannot determine GraphQL output type for getProducts - graphql

Question

I get this error when i try to return a custom dto from a resolver. (node:28156) UnhandledPromiseRejectionWarning: Error: Cannot determine GraphQL output type for getProducts
Here is what my code looks like.
product.entity.ts
import {
Entity,
Column,
PrimaryGeneratedColumn,
BaseEntity,
BeforeInsert,
} from 'typeorm';
import { ObjectType, Field, ID, Float, Int } from '#nestjs/graphql';
#ObjectType()
#Entity()
export class Product extends BaseEntity {
#Field(() => ID)
#PrimaryGeneratedColumn('uuid')
id: string;
#Column({ default: '', select: false })
ratingsString: string;
#Field(() => [Int])
ratings;
#BeforeInsert()
setRatingsString() {
this.ratingsString = this.ratings.join(',');
}
}
product.resolver.ts
import { Resolver, Query, Args, ResolveField, Int, Parent } from '#nestjs/graphql';
import { Product } from './product.entity';
import { ProductService } from './product.service';
#Resolver(() => Product)
export class ProductResolver {
constructor(private productService: ProductService) {}
#Query(() => GetProductDto, { name: 'products' })
async getProducts(#Args() page: number) {
return this.productService.getProducts(page);
}
}
product.service.ts
import { Injectable } from '#nestjs/common';
import { InjectRepository } from '#nestjs/typeorm';
import { Repository } from 'typeorm';
import { Product } from './product.entity';
import { GetProductDto } from './product.dto';
#Injectable()
export class ProductService {
constructor(
#InjectRepository(Product) private productRepo: Repository<Product>,
) {}
async getProducts(page: number): Promise<GetProductDto> {
const MAX_PRODUCT_PER_PAGE = 20;
const start = page < 1 ? 1 : page;
const [products, productsCount] = await this.productRepo.findAndCount({
skip: (start - 1) * MAX_PRODUCT_PER_PAGE,
take: MAX_PRODUCT_PER_PAGE,
});
const productList = products.map(product => {
product.ratings = product.ratingsString.split(',').map(Number);
delete product.ratingsString;
return product;
});
return {
products: productList,
total: productsCount,
};
}
}
product.dto.ts
import { Field, Int, InputType } from '#nestjs/graphql';
import { Product } from './product.entity';
#InputType()
export class GetProductDto {
#Field(() => [Product])
products: Product[];
#Field(() => Int)
total: number;
}
The expectation here is that when i call the products query i will recieve an object with products and total. Whee products will be my array of products. What am I doing wrong?

Answer 1

Turns out all I needed was to provide a argument to Args.
#Query(() => GetProductDto, { name: 'products' })
async getProducts(#Args('arg_the_client_will_it_with') page: number) {
return this.productService.getProducts(page);
}