graphql-compose
graphql-compose – provides a type registry with a bunch of methods for programmatic schema construction. It allows not only to extend types but also remove fields, interfaces, args. If you want to write your graphql schema generator – graphql-compose is a good instrument for you.
- provides methods for editing GraphQL output/input types (add/remove fields/args/interfaces)
- introduces
Resolver's– the named graphql fieldConfigs, which can be used for finding, updating, removing records - provides an easy way for creating relations between types via
Resolver's - provides converter from
OutputTypetoInputType - provides
projectionparser from AST - provides
GraphQL schema languagefor defining simple types - adds additional types
Date,Json
And a little bit more
graphql-compose-[plugin] – are declarative generators/plugins built on top of graphql-compose, which take some ORMs, schema definitions and create GraphQL Models from them or modify existing GraphQL Types.
Type generators built on top graphql-compose
- graphql-compose-json - generates GraphQL type from JSON (a good helper for wrapping REST APIs)
- graphql-compose-mongoose - generates GraphQL types from mongoose (MongoDB models) with Resolvers.
- graphql-compose-elasticsearch - generates GraphQL types from elastic mappings; ElasticSearch REST API proxy via GraphQL.
- graphql-compose-aws - expose AWS Cloud API via GraphQL
Utility plugins:
- graphql-compose-relay - reassemble GraphQL types with
Relayspecific things, likeNodetype and interface,globalId,clientMutationId. - graphql-compose-connection - generates
connectionResolver fromfindManyandcountResolvers. - graphql-compose-dataloader - adds DataLoader to graphql-composer resolvers.
Documentation
Live Demos
- graphql-compose.herokuapp.com - Live demo of GraphQL Server (9 models, 14 files, ~750 LOC)
- nodkz.github.io/relay-northwind - Live demo of Relay client working with the server above (8 crazy pages, 47 files, ~3000 LOC)
Examples
Please follow Quick Start Guide for the complete example.
Here is just a demo of ambiguity ways of types definitions:
import { schemaComposer} from 'graphql-compose';
// You may use SDL format for type definition
const CityTC = schemaComposer.createObjectTC(`
type City {
code: String!
name: String!
population: Number
countryCode: String
tz: String
}
`);
// Define type via Config object
const CountryTC = schemaComposer.createObjectTC({
name: 'Country',
fields: {
title: 'String',
geo: `type LonLat { lon: Float, lat: Float }`,
hoisting: {
type: () => AnotherTC,
description: `
You may wrap type in thunk for solving
hoisting problems when two types cross reference
each other.
`,
}
}
});
// Or via declarative methods define some additional fields
CityTC.addFields({
country: CountryTC, // some another Type
ucName: { // standard GraphQL like field definition
type: GraphQLString,
resolve: (source) => source.name.toUpperCase(),
},
currentLocalTime: { // extended GraphQL Compose field definition
type: 'Date',
resolve: (source) => moment().tz(source.tz).format(),
projection: { tz: true }, // load `tz` from database, when requested only `localTime` field
},
counter: 'Int', // shortening for only type definition for field
complex: `type ComplexType {
subField1: String
subField2: Float
subField3: Boolean
subField4: ID
subField5: JSON
subField6: Date
}`,
list0: {
type: '[String]',
description: 'Array of strings',
},
list1: '[String]',
list2: ['String'],
list3: [new GraphQLOutputType(...)],
list4: [`type Complex2Type { f1: Float, f2: Int }`],
});
// Add resolver method
CityTC.addResolver({
kind: 'query',
name: 'findMany',
args: {
filter: `input CityFilterInput {
code: String!
}`,
limit: {
type: 'Int',
defaultValue: 20,
},
skip: 'Int',
// ... other args if needed
},
type: [CityTC], // array of cities
resolve: async ({ args, context }) => {
return context.someCityDB
.findMany(args.filter)
.limit(args.limit)
.skip(args.skip);
},
});
// Remove `tz` field from schema
CityTC.removeField('tz');
// Add description to field
CityTC.extendField('name', {
description: 'City name',
});
schemaComposer.Query.addFields({
cities: CityTC.getResolver('findMany'),
currentTime: {
type: 'Date',
resolve: () => Date.now(),
},
});
schemaComposer.Mutation.addFields({
createCity: CityTC.getResolver('createOne'),
updateCity: CityTC.getResolver('updateById'),
...adminAccess({
removeCity: CityTC.getResolver('removeById'),
}),
});
function adminAccess(resolvers) {
Object.keys(resolvers).forEach(k => {
resolvers[k] = resolvers[k].wrapResolve(next => rp => {
// rp = resolveParams = { source, args, context, info }
if (!rp.context.isAdmin) {
throw new Error('You should be admin, to have access to this action.');
}
return next(rp);
});
});
return resolvers;
}
// construct schema which can be passed to express-graphql, apollo-server or graphql-yoga
export const schema = schemaComposer.buildSchema();Contributors
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