Types2graphql NPM

types2graphql - A minimal Typescript to GraphQL Converter

This lightweight library converts TypeScript interfaces into GraphQL types and inputs based on the __kind field specified in the interfaces. It's designed to be a simple solution for automatically generating GraphQL schemas from TypeScript interfaces.

Installation

Install the library using npm:

npm install types2graphql

Usage

1. Import the Library

import { typing, generateGraphQLSchema } from "types2graphql";

2. Define Your TypeScript Interfaces in a dedicated folder e.g. "interfaces/book.interface.ts"

interface Book {
  __kind: typing.TYPE;
  id: string;
  name: string;
  rating: number;
  authors: Author[];
}

interface Author {
  __kind: typing.TYPE;
  id: string;
  name: string;
  age?: number;
}

interface Filter {
  __kind: typing.INPUT;
  rating?: number;
}

interface Response {
  __kind: typing.TYPE;
  books: Book[];
}

3. Using generateGraphQLSchema() Function

// Provide the path to the folder containing the interfaces and a name for your graphQL app

generateGraphQLSchema(path.join(process.cwd(), "interfaces"), "sample");

This creates a file sample.graphql file where all the schemas found in the interfaces folder.

4. Manually Create Resolver File

Create a resolver.graphql file manually:

type Query {
  book(input: FilterInput): ResponseType
}

5. GraphQL Server Setup

import { ApolloServer } from 'apollo-server';
import fs from 'fs';

// Read the manually created resolver file
const graphqlSchema = fs.readFileSync('interfaces/sample.graphql', 'utf-8');
const resolverFile = fs.readFileSync('resolver.graphql', 'utf-8');

// Concatenate generated schema and resolver file
const schema = graphqlSchema + '\n' + resolverFile;

// In-memory array of 5 book objects (replace with your actual data)
const books = [...];

// GraphQL Query Resolver
const resolvers = {
  Query: {
    book: (_: any, { input }: any) => {
      // Implement your filter logic here
      // Return filtered books based on input
      return { books };
    },
  },
};

// Create an Apollo Server
const server = new ApolloServer({ typeDefs: schema, resolvers });

// Start the server
server.listen().then(({ url }) => {
  console.log(`Server ready at ${url}`);
});