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.

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Install GraphQL.js from npm

``sh
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.

`js
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.

`js
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.

`js
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);
});
`

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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!

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Read the Apollo Contributor Guidelines.

#### TypeScript

Part of this fork's purpose is to begin a gradual migration of graphql-js from Flow to TypeScript. Some parts have already been converted, and some remain to be converted. The steps for converting a file from Flow to TypeScript are as follows:

1. Rename the file, and convert syntax to TypeScript: Foo.js becomes Foo.ts, and any Flow specific syntax should be transalted.
2. Create a Foo.js.flow type declaration file for the file's exports (Foo.d.ts, if present, can be helpful for guiding this process). Make sure you prefix the file with // @flow, or else strange things will happen!
3. Delete the Foo.d.ts file, if it exists.
4. Run npm run check, and ensure both flow and tsc typecheck the project without issue.

Check out 45da517 for an example of this process.

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Changes are tracked as GitHub releases.

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GraphQL.js is MIT-licensed.

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The .d.ts files in this project are, in part, from @types/graphql`, written by:

- 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

And licensed under the MIT License.

Thanks to all the above contributors!