simple-graphql-assembler

simple-graphql-assembler

The main goal of this package is to create type definitions and resolvers based on the selected folder .gql and .resolver.js files. The main funtion will create the input tpyeDefs and resolvers for the AppolloServer by searching for .gql and .resolver.js files.

The .gql file formats are not validated, just simply reduced to a one string variable.

// hero.gql
type Hero {
  id: ID!
  name: String!
  actions: [Action]
}

extend type Query {
  heroes: [Hero]
  hero(id: ID!): Hero
}

It is required in the resolver modules to export a plain object with a __name property, because the package cannot figure out the key of the end resolver object.

// hero.resolver.js
const heroDb = require('../heroDb');

module.exports = {
  __name: 'Hero',

  actions(h) {
    return h.actions;
  },

  Query: {
    heroes() {
      return [...heroDb];
    },
    hero(_, { id }) {
      return heroDb.find(h => h.id === id);
    },
  },
};

The __name field will be removed from the final resolvers tree.

The gql file and resolver concatenations are separeted. The package will not search for specific resolver and type definition files. The patterns are based on the .gql extension and the .resolver.js postfix.

In the example i put the Query under the Hero resolver but it is not necessary, because the package will search for the Mutation or the Query named property in the resolver and moves them to the final tree in a separeted reduced property.

installation

npm

npm install simple-graphql-assembler

yarn

yarn add simple-graphql-assembler

usage

const { ApolloServer, gql } = require('apollo-server');
const assemble = require('simple-graphql-assembler');

const { typeDefs, resolvers, errors } = assemble(__dirname);
/*
The errors contains the validation errors.
Two specific rules:
   - Resolvers has to be a plain object
   - Resolvers must contain a __name property (String)
*/

// validation errors
if (errors) {
  console.log(errors);
  process.exit(1);
}

console.log(resolvers);
/*
{ Mutation: { addAction: [Function: addAction] },
  Action: { hero: [Function: hero] },
  Query: { heroes: [Function: heroes], hero: [Function: hero] },
  Hero: { actions: [Function: actions] } }
*/

const server = new ApolloServer({
  typeDefs: gql(typeDefs),
  resolvers,
});

server.listen().then(({ url }) => {
  console.log(`Example server listen at ${url}`);
});

cli usage

I added a tool for cli usage, the tool is called make-typedefs This tool will be traverse the current working directory for .gql files and with a very simple technique (copy) it will create one single file as a merged schema.gql.

Usage: make-typedefs [options]

Options:
  --version     Show version number                                    [boolean]
  --root, -r    Root folder of your gql definitions and resolvers [default: "."]
  --output, -o  Output file for type definitions       [default: "./schema.gql"]
  -h, --help    Show help                                              [boolean]

Examples:
  make-typedefs -r . -o ./schema.gql  Create the gql type definition file for
                                      your definitions from the current
                                      directory