TypeGraphql Field and Arg decorators using custom type - graphql

Question

I'm trying to build a resolver using type-graphql library and found that I can't define custom argument type. Here is my code:
type Hits = { [K: string]: string | number }
#Resolver()
export default class SearchResolver {
#Query(() => [String], { nullable: true })
#UseMiddleware(isAuthenticated)
async searchAssetList(#Arg('hits') hits: Hits) {
return [];
}
}
I got an error:
NoExplicitTypeError: Unable to infer GraphQL type from TypeScript reflection system. You need to provide explicit type for argument named 'hits' of 'searchAssetList' of 'SearchResolver' class.
I also tried to define an input class:
type Hits = { [K: string]: string | number }
#ObjectType()
class SearchListInput {
#Field(() => GraphQLObjectType)
hits: Hits;
}
#Resolver()
export default class SearchResolver {
#Query(() => [String], { nullable: true })
async searchAssetList(#Arg('input') input: SearchListInput) {
return []
}
}
and got another error:
UnhandledPromiseRejectionWarning: Error: Cannot determine GraphQL input type for argument named 'input' of 'searchAssetList' of 'SearchResolver' class. Is the value, that is used as its TS type or explicit type, decorated with a proper decorator or is it a proper input value?
Replacing #ObjectType with #InputType also doesn't help. How to define decorators like #Field, #Arg correctly?
Any help is appreciated. Thanks.

Answer 1

I think you are trying to have an Arg of an array whit numbers and strings in that case you should do
#InputType()
class HitsInput
{
#Field()
Hits: [number | string];
}
#Resolver()
export default class SearchResolver {
#Query(() => [String], { nullable: true })
async searchAssetList(#Arg('input') input: HitsInput) {
return []
}
}
if this is not the case and you want an object whit dynamic fields you need to define the object, let say if hits have Name and Id_Hits,
#InputType()
class HitsInput
{
#Field()
Id_Hits: number;
#Field()
Name: string;
}
#Resolver()
export default class SearchResolver {
#Query(() => [String], { nullable: true })
async searchAssetList(#Arg('input') input: HitsInput) {
return []
}
}
and if you want to have a dynamic args base in the user request I am not quite sure that it is possible, but it is possible to do this
#InputType()
class HitsInput
{
[key: string]: any;
}

Answer 2

I had exactly the same issue, a couple of days ago, and I solve it using GraphQLScalarType by creating my own custom type
here how to do it
import { GraphQLScalarType} from "graphql";
export const GraphQLAny = new GraphQLScalarType({
name: 'Any',
serialize: (value) => value,
parseValue: (value) => value,
parseLiteral: (ast) => ast
});
and in your class you can use your customTpe like this:
#ObjectType()
class SearchListInput {
#Field(() => GraphQLAny)
hits: typeof GraphQLAny;
}