GraphQL.js

A JavaScript implementation of GraphQL, a query language for APIs created by Facebook.

The purpose of this fork is to increase the velocity with which we at Apollo are able to improve the graphql implementation, while also gradually converting it from Flow to TypeScript.

See more complete documentation at https://graphql.org/ and https://graphql.org/graphql-js/.

Looking for help? Find resources from the community.

Getting Started

An overview of GraphQL in general is available in the README for the Specification for GraphQL. That overview describes a simple set of GraphQL examples that exist as tests in this repository. A good way to get started with this repository is to walk through that README and the corresponding tests in parallel.

Using GraphQL.js

Install GraphQL.js from npm

npm install --save @apollo/graphql

GraphQL.js provides two important capabilities: building a type schema, and serving queries against that type schema.

First, build a GraphQL type schema which maps to your code base.

import {
  graphql,
  GraphQLSchema,
  GraphQLObjectType,
  GraphQLString,
} from '@apollo/graphql';

var schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'RootQueryType',
    fields: {
      hello: {
        type: GraphQLString,
        resolve() {
          return 'world';
        },
      },
    },
  }),
});

This defines a simple schema with one type and one field, that resolves to a fixed value. The resolve function can return a value, a promise, or an array of promises. A more complex example is included in the top level tests directory.

Then, serve the result of a query against that type schema.

var query = '{ hello }';

graphql(schema, query).then(result => {
  // Prints
  // {
  //   data: { hello: "world" }
  // }
  console.log(result);
});

This runs a query fetching the one field defined. The graphql function will first ensure the query is syntactically and semantically valid before executing it, reporting errors otherwise.

var query = '{ boyhowdy }';

graphql(schema, query).then(result => {
  // Prints
  // {
  //   errors: [
  //     { message: 'Cannot query field boyhowdy on RootQueryType',
  //       locations: [ { line: 1, column: 3 } ] }
  //   ]
  // }
  console.log(result);
});

Using in a Browser

GraphQL.js is a general purpose library and can be used both in a Node server and in the browser. As an example, the GraphiQL tool is built with GraphQL.js!

Building a project using GraphQL.js with webpack or rollup should just work and only include the portions of the library you use. This works because GraphQL.js is distributed with both CommonJS (require()) and ESModule (import) files. Ensure that any custom build configurations look for .mjs files!

Contributing

Read the Apollo Contributor Guidelines.

Changelog

Changes are tracked as GitHub releases.

License

GraphQL.js is MIT-licensed.

TypeScript definition files

We used *.d.ts files from DefinetlyTyped as the basis for our TypeScript conversion in v15.0.0. Big thanks to:

• TonyYang https://github.com/TonyPythoneer
• Caleb Meredith https://github.com/calebmer
• Dominic Watson https://github.com/intellix
• Firede https://github.com/firede
• Kepennar https://github.com/kepennar
• Mikhail Novikov https://github.com/freiksenet
• Ivan Goncharov https://github.com/IvanGoncharov
• Hagai Cohen https://github.com/DxCx
• Ricardo Portugal https://github.com/rportugal
• Tim Griesser https://github.com/tgriesser
• Dylan Stewart https://github.com/dyst5422
• Alessio Dionisi https://github.com/adnsio
• Divyendu Singh https://github.com/divyenduz
• Brad Zacher https://github.com/bradzacher
• Curtis Layne https://github.com/clayne11
• Jonathan Cardoso https://github.com/JCMais
• Pavel Lang https://github.com/langpavel
• Mark Caudill https://github.com/mc0
• Martijn Walraven https://github.com/martijnwalraven
• Jed Mao https://github.com/jedmao