Create a schema for a GraphQL server
Server construction
GraphQL · Function
makeExecutableSchema
makeExecutableSchema combines GraphQL type definitions with resolvers to produce an executable schema. The result can be passed to a graphql-js-based server.
How it works
makeExecutableSchema combines GraphQL SDL and resolver maps into an executable schema. The resulting schema can be passed to a graphql-js server or used directly to execute operations.
Syntax
makeExecutableSchema({ typeDefs, resolvers })Parameters
| Name | Type | Description |
|---|---|---|
typeDefs | DocumentNode or SDL string | GraphQL schema definition language documents describing the types and fields. |
resolvers | Resolver map | Resolver functions and resolver maps implementing the schema fields. |
Returns
An executable GraphQL schema.
Key points
- The function is provided by the @graphql-tools/schema package.
- Create the executable schema by passing SDL definitions and resolver implementations in one options object.
- An executable schema can be exported from a generated module for reuse by application code.
- The returned schema is compatible with GraphQL servers built on graphql-js.
Common mistakes
- The type definitions and resolvers must be supplied together in the options object so the schema has both its structure and behavior.
Example: Build and query an executable schema
import { makeExecutableSchema } from "@graphql-tools/schema";
import { graphql } from "graphql";
const typeDefs = `
type Query { greeting: String! }
`;
const resolvers = {
Query: { greeting: () => "Hello, GraphQL!" },
};
const schema = makeExecutableSchema({ typeDefs, resolvers });
const result = await graphql({ schema, source: "{ greeting }" });
console.log(result.data);This builds a runnable schema from SDL type definitions and matching resolver functions, then executes a query against it.
When to use it
Run queries against a schema during development or testing
Local execution
Add middleware around an executable schema
Schema composition
Interview questions
QWhat does makeExecutableSchema produce?
makeExecutableSchema creates an executable GraphQL schema from type definitions and resolvers. The returned schema can be handed to a graphql-js-based server.
Follow-up: Why are both inputs needed? SDL describes the schema contract, while resolvers provide the runtime field behavior.
QWhat are the main inputs?
The function accepts an options object containing typeDefs and resolvers. The example on the official GraphQL site imports it from @graphql-tools/schema.
Follow-up: What would happen if a field had no resolver? GraphQL may use its default field resolver, but custom behavior must be supplied through the resolver map.
QHow is the result used?
After construction, the executable schema is suitable for use by a GraphQL server. It can also be composed with middleware before serving requests.
Follow-up: Why apply middleware after creation? Middleware can wrap schema execution or field behavior without changing the SDL definition itself.
Related
typeDefsresolversgraphql-jsapplyMiddleware