GraphTypeGen is a command-line tool that generates a fully-typed TypeScript library from your GraphQL schema files. It streamlines the process of creating type-safe query and mutation functions, making your codebase more maintainable, readable, and less error-prone.

• 🔒 Type-safe: Automatically generates TypeScript interfaces from your GraphQL types.
• ⚡ Fast & Efficient: Quickly produces ready-to-use TypeScript functions for queries and mutations.
• 🧩 Customizable: Add custom headers and specify client configurations (e.g., Apollo Client).
• 🚀 Error Handling: Optional built-in error handling for safer API calls.
• 📝 Clean Output: Organized, readable, and production-ready TypeScript code.

1. Provide a GraphQL Schema: Pass your .graphql or .gql schema file to the tool.
2. Configure Output: Specify the output path, client name (e.g., apolloClient), and optional error handling preferences.
3. Generate Code: The tool creates TypeScript interfaces for your GraphQL types and functions for your queries and mutations.

graph-type-gen \
  -schema="./schema.graphql" \
  -output="./generated/graphql.ts" \
  -header="import { gql } from '@apollo/client';" \
  -client="apolloClient" \
  -error="true"

• TypeScript interfaces matching your GraphQL types.
• Query and Mutation functions using your provided client.
• Automatic error handling (if -error flag is provided).

export interface User {
  id: string;
  name: string;
  email: string;
}

async function getUser(id: string): Promise<[User | null, any | null]> {
  try {
    const response = await apolloClient.query({
      query: gql(`
        query getUser($id: String) {
          getUser(id: $id) {
            id
            name
            email
          }
        }
      `),
      variables: { id },
    });
    return [response.data.getUser, null];
  } catch (error) {
    return [null, error];
  }
}

1. Clone the repository:

   git clone https://github.com/MichaelHoelzl/GraphTypeGen.git
   cd GraphTypeGen

2. Build and run the tool:

   go build -o graph-type-gen
   ./graph-type-gen -schema="./schema.graphql" -output="./generated.ts" -header="import { gql } from '@apollo/client';" -client="apolloClient"

This project is licensed under the MIT License – feel free to use and contribute!