How can GraphQL enable an ID based query at sub fields level? - graphql

Question

If an existing service supporting the following GraphQL queries respectively:
query to a person's bank account:
query {
balance(id: "1") {
checking
saving
}
}
result
{
"data": {
"balance": {
"checking": "800",
"saving": "3000"
}
}
}
query to a person's pending order:
query {
pending_order(id: "1") {
books
tickets
}
}
result
{
"data": {
"pending_order": {
"books": "5",
"tickets": "2"
}
}
}
The source code achieving the above functionality is something like this:
module.exports = new GraphQLObjectType({
name: 'Query',
description: 'Queries individual fields by ID',
fields: () => ({
balance: {
type: BalanceType,
description: 'Get balance',
args: {
id: {
description: 'id of the person',
type: GraphQLString
}
},
resolve: (root, { id }) => getBalance(id)
},
pending_order: {
type: OrderType,
description: 'Get the pending orders',
args: {
id: {
description: 'id of the person',
type: GraphQLString
}
},
resolve: (root, { id }) => getPendingOrders(id)
}
})
});
Now, I want to make my GraphQL service schema support person level schema, i.e.,
query {
person (id: "1") {
balance
pending_order
}
}
and get the following results:
{
"data": {
"balance": {
"checking": "800",
"saving": "3000"
}
"pending_order": {
"books": "5",
"tickets": "2"
}
}
}
How can I re-structure the schema, and how can I reuse the existing query service?
EDIT (after reading Daniel Rearden's answer):
Can we optimize the GraphQL service so that we make service call based upon the query? i.e., if the incoming query is
query {
person (id: "1") {
pending_order
}
}
my actually query becomes
person: {
...
resolve: (root, { id }) => Promise.all([
getBalance(id)
]) => ({ balance})
}

Answer 1

You're going to have to define a separate Person type to wrap the balance and pending_order fields.
module.exports = new GraphQLObjectType({
name: 'Person',
fields: () => ({
balance: {
type: BalanceType,
resolve: ({ id }) => getBalance(id)
},
pending_order: {
type: OrderType,
resolve: ({ id }) => getPendingOrders(id)
}
})
});
And you're going to need to add a new field to your Query type:
person: {
type: PersonType,
args: {
id: {
type: GraphQLString
}
},
// We just need to return an object with the id, the resolvers for
// our Person type fields will do the result
resolve: (root, { id }) => ({ id })
}
There's not much you can do to keep things more DRY and reuse your existing code. If you're looking for a way to reduce boilerplate, I would suggest using graphql-tools.