how to reuse resolvers in graphql - graphql

Question

I am new to graphql, I was creating following schema with graphql
// promotion type
const PromoType = new GraphQLObjectType({
name: 'Promo',
description: 'Promo object',
fields: () => ({
id: {
type: GraphQLID,
description: 'id of the promo'
},
title: {
type: GraphQLString,
description: 'this is just a test'
},
departments: {
type: new GraphQLList(DepartmentType),
description: 'departments associated with the promo'
}
})
})
and department type
// department type
const DepartmentType = new GraphQLObjectType({
name: 'Department',
description: 'Department object',
fields: () => ({
id: {
type: GraphQLID,
description: 'id of the department'
},
name: {
type: GraphQLString,
description: 'name of the department'
},
createdAt: {
type: GraphQLDate,
description: 'date the promo is created'
},
updatedAt: {
type: GraphQLDate,
description: 'date the promo is last updated'
}
})
});
and the following are the resolvers
// Promos resolver
const promos = {
type: new GraphQLList(PromoType),
resolve: (_, args, context) => {
let promos = getPromos()
let departments = getDepartmentsById(promos.promoId)
return merge(promos, departments)
}
};
//Departments resolver
const departments = {
type: new GraphQLList(DepartmentType),
args: {
promoId: {
type: GraphQLID
}
},
resolve: (_, args, context) => {
return getDepartmentsById(args.promoId)
}
};
the problem is I want to use the resolver of the departments into the resolver of the promos to get the departments.
I might be missing something obvious but is there any way to do this?

Answer 1

This is the way to do it. You want to think of it as graphs, rather than just a single rest endpoint.
To get data for Promo, you need to do it similarly to how I did it here, but for the parent node, if that makes sense. So, in e.g. viewer's resolve you add the query for Promo.
const PromoType = new GraphQLObjectType({
name: 'Promo',
description: 'Promo object',
fields: () => ({
id: {
type: GraphQLID,
description: 'id of the promo',
},
title: {
type: GraphQLString,
description: 'this is just a test',
},
departments: {
type: new GraphQLList(DepartmentType),
description: 'departments associated with the promo',
resolve: (rootValue) => {
return getDepartmentsById(rootValue.promoId);
}
}
})
});