Why won't GraphQL (on Node.js) call my "resolve" method? - graphql

Question

I'm trying to implement a very basic GraphQL interface in Node.js, but no matter what I do I can't seem to get the resolve method of my foo type to trigger. When I run the following code in a unit test it runs successfully, but I can see from the (lack of) console output that resolve wasn't called, and as a result I get an empty object back when I call graphql(FooSchema, query).
Can anyone more experienced with GraphQL suggest what I might be doing wrong? I'm completely baffled as to how the whole operation can even complete successfully if GraphQL can't find and call the method that is supposed to return the results ...
const fooType = new GraphQLInterfaceType({
name: `Foo`,
description: `A foo`,
fields: () => ({
id: {
description: `The foo's id`,
type: new GraphQLNonNull(GraphQLInt),
},
title: {
description: `The foo's title`,
type: new GraphQLNonNull(GraphQLString),
}
})
});
const queryType = new GraphQLObjectType({
fields: {
foo: {
args: {
id: {
description: 'ID of the foo',
type: new GraphQLNonNull(GraphQLString)
}
},
resolve: (root, { id }) => {
console.log(12345);
return getFoo(id)
},
type: fooType,
}
},
name: 'Query',
});
export default new GraphQLSchema({
query: queryType,
types: [fooType],
});
// In test:
const query = `
foo {
title
}
`;
const result = graphql(FooSchema, query); // == {}

Answer 1

const fooType = new GraphQLInterfaceType({
name: `Foo`,
description: `A foo`,
fields: () => ({
id: {
description: `The foo's id`,
type: new GraphQLNonNull(GraphQLInt),
},
title: {
description: `The foo's title`,
type: new GraphQLNonNull(GraphQLString),
}
})
});
This is an interface type, however your consumer queryType never implements it. A quick solution should be to change it to this:
const fooType = new GraphQLObjectType({
name: `Foo`,
description: `A foo`,
fields: () => ({
id: {
description: `The foo's id`,
type: new GraphQLNonNull(GraphQLInt),
},
title: {
description: `The foo's title`,
type: new GraphQLNonNull(GraphQLString),
}
})
});
Here's an example that works for me:
const {
GraphQLNonNull,
GraphQLInt,
GraphQLString,
GraphQLObjectType,
GraphQLSchema,
graphql,
} = require('graphql');
const fooType = new GraphQLObjectType({
name: `Foo`,
description: `A foo`,
fields: () => ({
id: {
description: `The foo's id`,
type: new GraphQLNonNull(GraphQLInt),
},
title: {
description: `The foo's title`,
type: new GraphQLNonNull(GraphQLString),
},
}),
});
const queryType = new GraphQLObjectType({
fields: {
foo: {
args: {
id: {
description: 'ID of the foo',
type: new GraphQLNonNull(GraphQLString),
},
},
resolve: (root, { id }) => {
return { id, title: 'some-title' };
},
type: fooType,
},
},
name: 'Query',
});
const schema = new GraphQLSchema({
query: queryType,
types: [fooType],
});
graphql(schema, `{ foo (id:"123") { id, title } }`).then(console.log.bind(console));
This should print:
$ node test.js
{ data: { foo: { id: 123, title: 'some-title' } } }
Here's the docs on the InterfaceType: http://graphql.org/learn/schema/#interfaces