nitrogql

Resolvers file reference

The resolvers type definition file expresses the types of resolvers you need to implement a GraphQL server. It is generated by the nitrogql generate command and written to the path specified by the generate.resolversOutput option.

Exported Types

Resolvers

Resolvers<Context> is the type of all resolvers. Usually, a GraphQL server accepts an object of this type as itsresolvers option.

Context is the type of the context object passed to resolvers.

Example usage:

import { Resolvers } from "./generated/resolvers";

type Context = {};
const resolvers: Resolvers<Context> = {
  // resolvers for top-level queries and mutations
  Query: { /* ... */ },
  Mutation: { /* ... */ },
  // resolvers for types
  User: { /* ... */ },
};

Resolver types for individual types are not exported directly. Instead, you can use some TypeScript trick to retrieve them.

import { Resolvers } from "./generated/resolvers";
const queryResolvers: Resolvers<Context>["Query"] = { /* ... */ };

ResolverOutput

By ResolverOutput<T> we mean the TypeScript type of the object returned by a resolver for a GraphQL type T. T should be a string literal type that is the name of a GraphQL type.

In other words, it is the model type of T; see nitrogql:model plugin references for more details about the idea of model types.

import { Resolvers, ResolverOutput } from "./generated/resolvers";

type Context = {};
const queryResolvers: Resolvers<Context>["Query"] = {
  /** get the current user */
  me: () => {
    // the type of the returned object is ResolverOutput<"User">
    return {
      id: "1",
      name: "John Doe",
    };
  }
};
const userResolvers: Resolvers<{}>["User"] = {
  email: async (user) => {
    // the type of `user` is ResolverOutput<"User">
    const email = await getEmail(user.id);
  }
}

ResolverOutput is useful when you want to give a name to the type of an object that should be returned by a resolver.