graphql-compose

9.1.0 verified Sat Apr 25 auth: no javascript

Programmatic GraphQL schema builder with a type registry for constructing and editing output/input types, fields, arguments, and interfaces. v9.1.0 (stable) supports GraphQL v14–16, ships TypeScript definitions, and is ESM-only. Key differentiators vs graphql-tools: Resolver abstraction for CRUD operations, built-in projection parser from AST, OutputType-to-InputType converter, and plugin ecosystem (mongoose, JSON, Elasticsearch). Releases ~monthly; recent fixes address security (removed object-path) and TypeScript compatibility.

Common errors

error TypeError: Cannot read properties of undefined (reading 'getType') ↓

cause Resolver referenced a type that hasn't been added to the schemaComposer yet.

fix

Ensure the type is created (e.g., schemaComposer.createObjectTC) before referencing it in resolver type field.

error Error: Schema must contain uniquely named types but contains multiple types named "Query". ↓

cause Accidentally created duplicate root types via schemaComposer.Query.addFields() and schemaComposer.createObjectTC({ name: 'Query'}).

fix

Do not create an object type composer with same name as root types. Use schemaComposer.Query directly.

error GraphQLError: Field "user" must not have a selection since type "User" has no subfields. ↓

cause Resolver type is set to UserTC but resolver does not return object; or query selects subfields but schema built incorrectly.

fix

Verify resolver returns an object matching UserTC fields and that schemaComposer.buildSchema() is called after adding resolvers.

error Module not found: Can't resolve 'graphql' in ... ↓

cause Missing graphql peer dependency.

fix

npm install graphql@^14.2.0 || ^15.0.0 || ^16.0.0

Warnings

breaking v9 dropped support for GraphQL v13 and older; peer dependency now requires graphql@^14.2.0 || ^15.0.0 || ^16.0.0 ↓

fix Upgrade graphql to v14, v15, or v16. If locked to v13, stay on graphql-compose v8.

breaking v9 is ESM-only; CommonJS require() will fail. ↓

fix Use import statements or dynamic import(). If CJS required, stick with v8.

deprecated Removed object-path dependency due to security alerts; use native lodash.get or optional chaining. ↓

fix If using deep path access, migrate to ES2020 optional chaining or lodash.get.

gotcha schemaComposer is a singleton; importing it multiple times yields the same instance. Do not create new instances with new SchemaComposer() unless you intend separate registries. ↓

fix Use import { schemaComposer } for shared app schema; use new SchemaComposer() for isolated test contexts.

deprecated ObjectTypeComposer.setField() mutates the type in-place; future versions may prefer immutable patterns. ↓

fix Consider using addFields or removeField methods; check for deprecation warnings in v10.

Install

npm install graphql-compose

yarn add graphql-compose

pnpm add graphql-compose

Imports

schemaComposer
wrong
```
const schemaComposer = require('graphql-compose').schemaComposer
```
correct
```
import { schemaComposer } from 'graphql-compose'
```
Default export is not available; named export only. Since v9, ESM-only; use import statement.

ObjectTypeComposer

wrong

import ObjectTypeComposer from 'graphql-compose'

correct

import { ObjectTypeComposer } from 'graphql-compose'

Named export for type composer; default export does not exist.

Resolver
```
import { Resolver } from 'graphql-compose'
```
Resolver class for defining named GraphQL field configs.

GraphQLDate

wrong

const { GraphQLDate } = require('graphql-compose')

correct

import { GraphQLDate } from 'graphql-compose'

Custom scalar; use named import.

graphql-compose types
```
import type { ObjectTypeComposer } from 'graphql-compose'
```
Import types when only type information is needed (TS).

Quickstart

Creates an object type composer for User, adds a resolver, attaches to Query root, builds schema.

import { schemaComposer, ObjectTypeComposer, Resolver } from 'graphql-compose';
import { GraphQLSchema, GraphQLObjectType, GraphQLString } from 'graphql';

const UserTC = schemaComposer.createObjectTC({
  name: 'User',
  fields: {
    id: 'ID!',
    name: 'String!',
  },
});

UserTC.addResolver({
  name: 'findById',
  type: UserTC,
  args: { id: 'ID!' },
  resolve: async ({ args }) => {
    // pretend to fetch from DB
    return { id: args.id, name: 'John' };
  },
});

schemaComposer.Query.addFields({
  user: UserTC.getResolver('findById'),
});

const schema = schemaComposer.buildSchema();
console.log(schema);
// schema ready to be used with express-graphql or other server