graphql
Advanced tools
Package description
The graphql npm package is the JavaScript reference implementation for GraphQL, a query language for APIs and a runtime for executing those queries by using a type system you define for your data. It allows you to create schemas, define resolvers, and execute GraphQL queries and mutations.
Creating a GraphQL Schema
This feature allows you to define the shape of your data and the way it can be queried by clients. The code sample demonstrates how to create a simple GraphQL schema with a single root query.
const { GraphQLSchema, GraphQLObjectType, GraphQLString } = require('graphql');
const schema = new GraphQLSchema({
query: new GraphQLObjectType({
name: 'RootQueryType',
fields: {
hello: {
type: GraphQLString,
resolve() {
return 'Hello world!';
}
}
}
})
});Executing a GraphQL Query
This feature allows you to execute GraphQL queries against your schema. The code sample shows how to execute a simple query that asks for the 'hello' field, which resolves to 'Hello world!'.
const { graphql, buildSchema } = require('graphql');
const schema = buildSchema(`
type Query {
hello: String
}
`);
const root = { hello: () => 'Hello world!' };
graphql(schema, '{ hello }', root).then((response) => {
console.log(response);
});Defining Resolvers
Resolvers are functions that resolve the value for a type or field in a schema. The code sample shows how to define a resolver for the 'hello' field that returns a string.
const { GraphQLObjectType, GraphQLString } = require('graphql');
const RootQueryType = new GraphQLObjectType({
name: 'RootQuery',
fields: {
hello: {
type: GraphQLString,
resolve() {
return 'Hello world!';
}
}
}
});Apollo Server is a community-driven, open-source GraphQL server that works with many Node.js HTTP server frameworks. It simplifies building a GraphQL API by providing features like performance tracing and schema stitching. Compared to graphql, Apollo Server offers a more integrated set of tools for building production-ready GraphQL services.
Express GraphQL is a GraphQL HTTP server middleware for Express.js. It allows you to serve a GraphQL API as a web service. While graphql provides the core functionality for schema creation and query execution, express-graphql makes it easy to integrate GraphQL with the Express web application framework.
TypeGraphQL is a framework for building GraphQL APIs in Node.js using TypeScript, based on the official graphql-js package. It allows for defining the schema using TypeScript classes and decorators, which can be more familiar to developers with an object-oriented background. It provides a more type-safe and class-based approach to defining GraphQL schemas compared to the more traditional, function-based approach of graphql.
Readme
This is a technical preview of the JavaScript reference implementation for GraphQL, a query language created by Facebook for describing data requirements on complex application data models.
See more complete documentation at http://graphql.org/ and http://graphql.org/docs/api-reference-graphql/.
For questions, ask Stack Overflow.
For discussion, join #graphql on Discord.
This technical preview contains a [draft specification for GraphQL] (https://github.com/facebook/graphql) and a reference implementation in JavaScript that implements that draft, GraphQL.js.
The reference implementation provides base libraries in JavaScript that would provide the basis for full GraphQL implementations and tools. It is not a fully standalone GraphQL server that a client developer could use to start manipulating and querying data. Most importantly, it provides no mapping to a functioning, production-ready backend. The only "backend" we have targeted for this early preview are in-memory stubs in test cases.
We are releasing this now because after GraphQL was first discussed publicly, many engineers used this information to implement the parts of the system that we discussed publicly. We want to support those engineers by providing both a formal specification and a reference implementation for the system as a whole.
To that end, the target audience is not the client developer, but those who have built or are actively interested in building their own GraphQL implementations and tools. Critically, we also want feedback on the system and to incorporate that feedback in our final release.
In order to be broadly adopted, GraphQL will have to target a wide variety of backends, frameworks, and languages, which will necessitate a collaborative effort across projects and organizations. This technical preview marks the beginning of that process.
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.
Install GraphQL.js from npm
npm install --save 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 '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);
});
The npm branch in this repository is automatically maintained to be the last
commit to master to pass all tests, in the same form found on npm. It is
recommend to use builds deployed npm for many reasons, but if you want to use
the latest not-yet-released version of graphql-js, you can do so by depending
directly on this branch:
npm install graphql@git://github.com/graphql/graphql-js.git#npm
We actively welcome pull requests, learn how to contribute.
Changes are tracked as Github releases.
GraphQL is BSD-licensed. We also provide an additional patent grant.
FAQs
A Query Language and Runtime which can target any service.
The npm package graphql receives a total of 12,165,366 weekly downloads. As such, graphql popularity was classified as popular.
We found that graphql demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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