GraphQL pass args to sub resolve
You can use the resolver fouth argument, info
, to receive the desired variable - from Apollo docs:
Every resolver in a GraphQL.js schema accepts four positional arguments:
fieldName(obj, args, context, info) { result }
These arguments have the following meanings and conventional names:
obj: The object that contains the result returned from the resolver on the parent field, or, in the case of a top-level Query field, the rootValue passed from the server configuration. This argument enables the nested nature of GraphQL queries.
args: An object with the arguments passed into the field in the query. For example, if the field was called with author(name: "Ada"), the args object would be: { "name": "Ada" }.
context: This is an object shared by all resolvers in a particular query, and is used to contain per-request state, including authentication information, dataloader instances, and anything else that should be taken into account when resolving the query. If you're using Apollo Server, read about how to set the context in the setup documentation.
info: This argument should only be used in advanced cases, but it contains information about the execution state of the query, including the field name, path to the field from the root, and more. It's only documented in the GraphQL.js source code.
The info
seems to be a very undocumented feature, but I'm using it now with no problems (at least until somebody decide to change it).
Here is the trick:
const UserType = new GraphQLObjectType({
name: 'User'
fields: () => ({
name: {
type: GraphQLString
},
posts: {
type: new GraphQLList(PostType),
resolve(parent, args , { db }, info) {
// I want to get here the args.someBooleanArg
console.log("BINGO!");
console.log(info.variableValues.someBooleanArg);
return someLogicToGetUserPosts();
}
}
})
});
When resolving the root query you can use object assign to attach the argument to the user object returned. Then, on the user type, resolve the argument from the root value (first argument of resolve function).
Example:
const queryType = new GraphQLObjectType({
name: 'RootQuery',
fields: {
users: {
type: new GraphQLList(UserType),
args: {
id: {
type: GraphQLInt
},
someBooleanArg: {
type: GraphQLInt
}
},
resolve: (root, { id, someBooleanArg }, { db }) => {
return Promise.resolve(someLogicToGetUsers()).then(v => {
return Object.assign({}, v, {
someBooleanArg
});
});
}
}
}
});
const UserType = new GraphQLObjectType({
name: 'User'
fields: () => ({
name: {
type: GraphQLString
},
posts: {
type: new GraphQLList(PostType),
resolve(parent, args , { db }) {
console.log(parent.someBooleanArg);
return someLogicToGetUserPosts();
}
}
})
});