08-Codegen.md

Code generation

You can use the codegen command to generate code (e.g. TypeScript type definitions) for the types of your GraphQL schema or related to GraphQL bindings.

Get schema for an endpoint

With graphql get-schema command, it is possible to get the schema SDL for a live GraphQL endpoint.

Assume the following .graphqlconfig:

projects:
  hello-world:
    schemaPath: schema.graphql
    extensions:
      endpoints:
        dev: https://myapiserver.com/graphql/dev

You can use the following variations of graphql get-schema command to replace the local schema with the live schema at the endpoint via introspection.

graphql get-schema --project hello-world

graphql get-schema --endpoint http://some-graphql-endpoint

And there are various other options available that can be found by typing graphql get-schema help

Generate Typescript typings for a project

With graphql codegen command, it is possible to generate typescript typings based on schema and TS files. A Typescript typings generator is built into the CLI and can be use by using generator as typegen is codegen extension via the graphql config file.

Assume the following .graphqlconfig:

projects:
  hello-world:
    schemaPath: schema.graphql
    extensions:
      endpoints:
        dev: https://myapiserver.com/graphql/dev
      codegen: 
        generator: typegen
        language: typescript
        input: "{binding,prisma}/*.ts"
        output:
          typings: typings.ts

Running graphql codegen will generate Typescript bindings and save them in the file typings.ts.

Generating type definitions for a GraphQL binding

Codegen can also create full Typescript binding for a GraphQL binding like Prisma binding based on a schema.

Assume the following .graphqlconfig:

projects:
  hello-world:
    schemaPath: schema.graphql
    extensions:
      endpoints:
        dev: https://myapiserver.com/graphql/dev
      codegen: 
        generator: prisma-binding
        language: typescript
        output:
          binding: prisma.ts

Running graphql codegen with such a graphql config file will generate Prisma binding.