wegiangb / neo4j-graphql-js

A GraphQL to Cypher query execution layer for Neo4j and JavaScript GraphQL implementations.

neo4j-graphql.js

A GraphQL to Cypher query execution layer for Neo4j and JavaScript GraphQL implementations.

• Read the docs
• Read the changelog

neo4j-graphql-js is in active development. There are rough edges and APIs may change. Please file issues for any bugs that you find or feature requests.

Installation and usage

Install

npm install --save neo4j-graphql-js

Usage

Start with GraphQL type definitions:

const typeDefs = `
type Movie {
    title: String
    year: Int
    imdbRating: Float
    genres: [Genre] @relation(name: "IN_GENRE", direction: "OUT")
}
type Genre {
    name: String
    movies: [Movie] @relation(name: "IN_GENRE", direction: "IN")
}
`;

Create an executable schema with auto-generated resolvers for Query and Mutation types, ordering, pagination, and support for computed fields defined using the @cypher GraphQL schema directive:

import { makeAugmentedSchema } from 'neo4j-graphql-js';

const schema = makeAugmentedSchema({ typeDefs });

Create a neo4j-javascript-driver instance:

import { v1 as neo4j } from 'neo4j-driver';

const driver = neo4j.driver(
  'bolt://localhost:7687',
  neo4j.auth.basic('neo4j', 'letmein')
);

Use your favorite JavaScript GraphQL server implementation to serve your GraphQL schema, injecting the Neo4j driver instance into the context so your data can be resolved in Neo4j:

import { ApolloServer } from 'apollo-server';

const server = new ApolloServer({ schema, context: { driver } });

server.listen(3003, '0.0.0.0').then(({ url }) => {
  console.log(`GraphQL API ready at ${url}`);
});

If you don't want auto-generated resolvers, you can also call neo4jgraphql() in your GraphQL resolver. Your GraphQL query will be translated to Cypher and the query passed to Neo4j.

import { neo4jgraphql } from 'neo4j-graphql-js';

const resolvers = {
  Query: {
    Movie(object, params, ctx, resolveInfo) {
      return neo4jgraphql(object, params, ctx, resolveInfo);
    }
  }
};

What is neo4j-graphql.js

A package to make it easier to use GraphQL and Neo4j together. neo4j-graphql.js translates GraphQL queries to a single Cypher query, eliminating the need to write queries in GraphQL resolvers and for batching queries. It also exposes the Cypher query language through GraphQL via the @cypher schema directive.

Goals

• Translate GraphQL queries to Cypher to simplify the process of writing GraphQL resolvers
• Allow for custom logic by overriding of any resolver function
• Work with graphql-tools, graphql-js, and apollo-server
• Support GraphQL servers that need to resolve data from multiple data services/databases
• Expose the power of Cypher through GraphQL via the @cypher directive

Benefits

• Send a single query to the database
• No need to write queries for each resolver
• Exposes the power of the Cypher query language through GraphQL

Test

We use the ava test runner.

npm install
npm build
npm test

The npm test script will run unit tests that check GraphQL -> Cypher translation and the schema augmentation features and can be easily run locally without a test environment. Full integration tests can be found in /test and are run on CircleCI as part of the CI process.

Examples

See /examples

Documentation

Full docs can be found on GRANDstack.io/docs