@constructive-io/graphql-codegen

Generate GraphQL mutations/queries

npm install @constructive-io/graphql-codegen

introspecting via GraphQL

import {
  generate
} from '@constructive-io/graphql-codegen';
import { print } from 'graphql/language';

const gen = generate(resultOfIntrospectionQuery);
const output = Object.keys(gen).reduce((m, key) => {
  m[key] = print(gen[key].ast);
  return m;
}, {});

console.log(output);

output

which will output the entire API as an object with the mutations and queries as values

{
  "createApiTokenMutation": "mutation createApiTokenMutation($id: UUID, $userId: UUID!, $accessToken: String, $accessTokenExpiresAt: Datetime) {
  createApiToken(input: {apiToken: {id: $id, userId: $userId, accessToken: $accessToken, accessTokenExpiresAt: $accessTokenExpiresAt}}) {
    apiToken {
      id
      userId
      accessToken
      accessTokenExpiresAt
    }
  }
}

Codegen (types, operations, SDK, React Query)

Programmatic codegen generates files to disk from a schema SDL file or from a live endpoint via introspection.

import { runCodegen, defaultGraphQLCodegenOptions } from '@constructive-io/graphql-codegen'

await runCodegen({
  input: { schema: './schema.graphql' }, // or: { endpoint: 'http://localhost:3000/graphql', headers: { Host: 'meta8.localhost' } }
  output: defaultGraphQLCodegenOptions.output, // root/typesFile/operationsDir/sdkFile/reactQueryFile
  documents: defaultGraphQLCodegenOptions.documents, // format: 'gql'|'ts', naming convention
  features: { emitTypes: true, emitOperations: true, emitSdk: true, emitReactQuery: true },
  reactQuery: { fetcher: 'graphql-request' }
}, process.cwd())

Outputs under output.root:

• types/generated.ts (schema types)
• operations/* (queries/mutations/Fragments)
• sdk.ts (typed GraphQL Request client)
• react-query.ts (typed React Query hooks; generated when emitReactQuery: true)

Documents options:

• format: 'gql' | 'ts'
• convention: 'dashed' | 'underscore' | 'camelcase' | 'camelUpper'
• allowQueries, excludeQueries, excludePatterns to control which root fields become operations

Endpoint introspection:

• Set input.endpoint and optional input.headers
• If your dev server routes by hostname, add headers: { Host: 'meta8.localhost' }

Selection Options

Configure result field selections, mutation input style, and connection pagination shape.

selection: {
  defaultMutationModelFields?: string[]
  modelFields?: Record<string, string[]>
  mutationInputMode?: 'expanded' | 'model' | 'raw' | 'patchCollapsed'
  connectionStyle?: 'nodes' | 'edges'
  forceModelOutput?: boolean
}

• defaultMutationModelFields

  • Sets default fields selected from the object payload returned by mutations when the mutation exposes an OBJECT output.
  • Example: ['id'] will select only the id from the returned model unless overridden per model.

• modelFields

  • Per‑model overrides for returned object payload fields.
  • Example: { domain: ['id','domain','subdomain'] } selects those fields from the domain object output.

• mutationInputMode

  • Controls how mutation variables and input are generated.
  • expanded: one variable per input property; input is a flat object of those variables.
  • model: one variable per property; variables are nested under the singular model key inside input.
  • raw: a single $input: <CreateXInput>! variable passed directly as input: $input.
  • patchCollapsed: a single $patch: <ModelPatch>! plus required locator(s) (e.g., $id), passed as input: { id: $id, patch: $patch }.

• connectionStyle

  • Standardizes connection queries and nested many selections.
  • nodes: emits totalCount and nodes { ... }.
  • edges: emits totalCount, pageInfo { ... }, and edges { cursor node { ... } }.

• forceModelOutput

  • When true, ensures the object payload is selected even if defaultMutationModelFields is empty, defaulting to ['id'].
  • Useful to avoid generating mutations that only return clientMutationId.

Examples

Create mutation with raw input:

mutation createDomain($input: CreateDomainInput!) {
  createDomain(input: $input) {
    domain { id, domain, subdomain }
  }
}

Patch mutation with collapsed patch:

mutation updateDomain($id: UUID!, $patch: DomainPatch!) {
  updateDomain(input: { id: $id, patch: $patch }) {
    domain { id }
    clientMutationId
  }
}

Edges‑style connection query:

query getDomainsPaginated($first: Int, $after: Cursor) {
  domains(first: $first, after: $after) {
    totalCount
    pageInfo { hasNextPage hasPreviousPage endCursor startCursor }
    edges { cursor node { id domain subdomain } }
  }
}

Custom Scalars and Type Overrides

• When your schema exposes custom scalars that are not available in the printed SDL or differ across environments, you can configure both TypeScript scalar typings and GraphQL type names used in generated operations.

• Add these to your config object:

{
  "scalars": {
    "LaunchqlInternalTypeHostname": "string",
    "PgpmInternalTypeHostname": "string"
  },
  "typeNameOverrides": {
    "LaunchqlInternalTypeHostname": "String",
    "PgpmInternalTypeHostname": "String"
  }
}

• scalars: maps GraphQL scalar names to TypeScript types for typescript/typescript-operations/typescript-graphql-request/typescript-react-query plugins.

• typeNameOverrides: rewrites scalar names in generated GraphQL AST so variable definitions and input fields use compatible built‑in GraphQL types.

• These options are also available programmatically through LaunchQLGenOptions.

Education and Tutorials

1. 🚀 Quickstart: Getting Up and Running Get started with modular databases in minutes. Install prerequisites and deploy your first module.

2. 📦 Modular PostgreSQL Development with Database Packages Learn to organize PostgreSQL projects with pgpm workspaces and reusable database modules.

3. ✏️ Authoring Database Changes Master the workflow for adding, organizing, and managing database changes with pgpm.

4. 🧪 End-to-End PostgreSQL Testing with TypeScript Master end-to-end PostgreSQL testing with ephemeral databases, RLS testing, and CI/CD automation.

5. ⚡ Supabase Testing Use TypeScript-first tools to test Supabase projects with realistic RLS, policies, and auth contexts.

6. 💧 Drizzle ORM Testing Run full-stack tests with Drizzle ORM, including database setup, teardown, and RLS enforcement.

7. 🔧 Troubleshooting Common issues and solutions for pgpm, PostgreSQL, and testing.

Related Constructive Tooling

🧪 Testing

• pgsql-test: 📊 Isolated testing environments with per-test transaction rollbacks—ideal for integration tests, complex migrations, and RLS simulation.
• supabase-test: 🧪 Supabase-native test harness preconfigured for the local Supabase stack—per-test rollbacks, JWT/role context helpers, and CI/GitHub Actions ready.
• graphile-test: 🔐 Authentication mocking for Graphile-focused test helpers and emulating row-level security contexts.
• pg-query-context: 🔒 Session context injection to add session-local context (e.g., SET LOCAL) into queries—ideal for setting role, jwt.claims, and other session settings.

🧠 Parsing & AST

• pgsql-parser: 🔄 SQL conversion engine that interprets and converts PostgreSQL syntax.
• libpg-query-node: 🌉 Node.js bindings for libpg_query, converting SQL into parse trees.
• pg-proto-parser: 📦 Protobuf parser for parsing PostgreSQL Protocol Buffers definitions to generate TypeScript interfaces, utility functions, and JSON mappings for enums.
• @pgsql/enums: 🏷️ TypeScript enums for PostgreSQL AST for safe and ergonomic parsing logic.
• @pgsql/types: 📝 Type definitions for PostgreSQL AST nodes in TypeScript.
• @pgsql/utils: 🛠️ AST utilities for constructing and transforming PostgreSQL syntax trees.

🚀 API & Dev Tools

• @constructive-io/graphql-server: ⚡ Express-based API server powered by PostGraphile to expose a secure, scalable GraphQL API over your Postgres database.
• @constructive-io/graphql-explorer: 🔎 Visual API explorer with GraphiQL for browsing across all databases and schemas—useful for debugging, documentation, and API prototyping.

🔁 Streaming & Uploads

• etag-hash: 🏷️ S3-compatible ETags created by streaming and hashing file uploads in chunks.
• etag-stream: 🔄 ETag computation via Node stream transformer during upload or transfer.
• uuid-hash: 🆔 Deterministic UUIDs generated from hashed content, great for deduplication and asset referencing.
• uuid-stream: 🌊 Streaming UUID generation based on piped file content—ideal for upload pipelines.
• @constructive-io/s3-streamer: 📤 Direct S3 streaming for large files with support for metadata injection and content validation.
• @constructive-io/upload-names: 📂 Collision-resistant filenames utility for structured and unique file names for uploads.

🧰 CLI & Codegen

• pgpm: 🖥️ PostgreSQL Package Manager for modular Postgres development. Works with database workspaces, scaffolding, migrations, seeding, and installing database packages.
• @constructive-io/cli: 🖥️ Command-line toolkit for managing Constructive projects—supports database scaffolding, migrations, seeding, code generation, and automation.
• @constructive-io/graphql-codegen: ✨ GraphQL code generation (types, operations, SDK) from schema/endpoint introspection.
• @constructive-io/query-builder: 🏗️ SQL constructor providing a robust TypeScript-based query builder for dynamic generation of SELECT, INSERT, UPDATE, DELETE, and stored procedure calls—supports advanced SQL features like JOIN, GROUP BY, and schema-qualified queries.
• @constructive-io/graphql-query: 🧩 Fluent GraphQL builder for PostGraphile schemas. ⚡ Schema-aware via introspection, 🧩 composable and ergonomic for building deeply nested queries.

Credits

🛠 Built by the Constructive team — creators of modular Postgres tooling for secure, composable backends. If you like our work, contribute on GitHub.

Disclaimer

AS DESCRIBED IN THE LICENSES, THE SOFTWARE IS PROVIDED "AS IS", AT YOUR OWN RISK, AND WITHOUT WARRANTIES OF ANY KIND.

No developer or entity involved in creating this software will be liable for any claims or damages whatsoever associated with your use, inability to use, or your interaction with other users of the code, including any direct, indirect, incidental, special, exemplary, punitive or consequential damages, or loss of profits, cryptocurrencies, tokens, or anything else of value.