@auto-engineer/server-generator-nestjs

| | |
| --- | --- |
| Status | EXPERIMENTAL - NOT READY FOR PRODUCTION |
| Stability | APIs will change without notice |
| Completeness | Features may be incomplete or broken |

Generates complete NestJS servers from narrative domain models with CQRS, GraphQL, and MikroORM.

---

Purpose

Without @auto-engineer/server-generator-nestjs, you would have to manually scaffold NestJS modules, wire up CQRS command/query handlers, configure GraphQL resolvers, define MikroORM entities, and write boilerplate test files for every domain slice.

This package takes a narrative model (JSON) describing your domain flows and slices, then generates a fully functional NestJS server with:

- CQRS pattern via @nestjs/cqrs for command and query separation
- GraphQL API via Apollo Server with auto-generated resolvers
- MikroORM entities with SQLite persistence
- Test scaffolds for each command handler

The generated server is immediately runnable and provides a foundation for domain-driven development.

---

Installation

``bash
pnpm add @auto-engineer/server-generator-nestjs
`

Quick Start

This package generates NestJS servers from domain models. Here is how to use it.

$3

`typescript
import { COMMANDS } from "@auto-engineer/server-generator-nestjs";
import { createMessageBus } from "@auto-engineer/message-bus";

const bus = createMessageBus();
COMMANDS.forEach((cmd) => bus.register(cmd));
`

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`typescript
const result = await bus.send({
type: "GenerateServer",
data: {
modelPath: ".context/model.json",
destination: ".",
},
});

console.log(result);
// → { type: 'ServerGenerated', data: { serverDir: './server', ... } }
`

The command reads your model file, generates a complete NestJS server in the server/ directory, and installs dependencies automatically.

---

How-to Guides

$3

`bash
auto generate:server --model-path=.context/model.json --destination=.
`

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`typescript
import { commandHandler } from "@auto-engineer/server-generator-nestjs";

const result = await commandHandler.handle({
type: "GenerateServer",
data: {
modelPath: ".context/model.json",
destination: "/path/to/project",
},
requestId: "req-123",
});
`

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`typescript
if (result.type === "ServerGenerationFailed") {
console.error(result.data.error);
}
`

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The handler emits SliceGeneratedEvent for each domain slice processed:

`typescript
const events = await commandHandler.handle(command);

for (const event of events) {
if (event.type === "SliceGenerated") {
console.log(Generated: ${event.data.flowName}.${event.data.sliceName});
}
}
`

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`bash
DEBUG=auto:server-generator-nestjs:* pnpm auto generate:server
`

Available debug namespaces:

- auto:server-generator-nestjs - General operation logging
- auto:server-generator-nestjs:schema - Model parsing details
- auto:server-generator-nestjs:files - File copy operations
- auto:server-generator-nestjs:deps - Dependency installation
- auto:server-generator-nestjs:scaffold - Scaffold generation

---

API Reference

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`typescript
import { COMMANDS } from "@auto-engineer/server-generator-nestjs";

import type {
GenerateServerCommand,
GenerateServerEvents,
ServerGeneratedEvent,
ServerGenerationFailedEvent,
SliceGeneratedEvent,
} from "@auto-engineer/server-generator-nestjs";
`

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| Command | CLI Alias | Description |
| ---------------- | ----------------- | --------------------------------- |
| GenerateServer | generate:server | Generate NestJS server from model |

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| Field | Type | Required | Description |
| ------------- | -------- | -------- | ------------------------------------------ |
| modelPath | string | Yes | Path to the JSON model file |
| destination | string | Yes | Destination directory for generated server |

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| Event | Description |
| ----------------------------- | -------------------------------- |
| ServerGeneratedEvent | Emitted on successful generation |
| ServerGenerationFailedEvent | Emitted when generation fails |
| SliceGeneratedEvent | Emitted for each slice processed |

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`typescript
{
modelPath: string;
destination: string;
serverDir: string;
contextSchemaGraphQL?: string;
}
`

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`typescript
{
modelPath: string;
destination: string;
error: string;
}
`

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`typescript
{
flowName: string;
sliceName: string;
sliceType: string;
schemaPath: string;
slicePath: string;
}
`

---

Architecture

`
src/
├── index.ts # Package entry point (exports COMMANDS)
├── commands/
│ └── generate-server.ts # Main command handler
├── codegen/
│ ├── scaffoldFromSchema.ts # Scaffold orchestrator
│ ├── entity-consolidation.ts # Entity field merging
│ ├── types.ts # Core type definitions
│ ├── extract/ # Message/GWT extraction
│ │ ├── commands.ts # Command extraction
│ │ ├── events.ts # Event extraction
│ │ ├── states.ts # State extraction
│ │ ├── fields.ts # Field extraction
│ │ ├── gwt.ts # GWT mapping builders
│ │ ├── graphql.ts # GraphQL query parsing
│ │ └── imports.ts # Cross-slice imports
│ ├── templates/ # EJS templates
│ │ ├── command/ # Command slice templates
│ │ ├── query/ # Query slice templates
│ │ ├── entity/ # Entity templates
│ │ └── module/ # NestJS module templates
│ └── utils/
│ └── path.ts # Path utilities
└── shared/ # Files copied to generated server
├── main.ts # NestJS bootstrap
├── mikro-orm.config.ts # Database configuration
└── graphql-types.ts # Shared GraphQL types
`

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The command generates the following structure:

`
server/
├── package.json
├── tsconfig.json
├── vitest.config.ts
├── mikro-orm.config.ts
└── src/
├── main.ts
└── domain/
├── shared/
│ └── graphql-types.ts
├── {flow-name}/
│ ├── {slice-name}/
│ │ ├── command.ts
│ │ ├── input.ts
│ │ ├── handler.ts
│ │ ├── handler.specs.ts
│ │ └── resolver.ts
│ └── entities/
│ └── {entity}.entity.ts
└── {flow-name}.module.ts
`

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Monorepo:

| Package | Usage |
| -------------------------- | ----------------------------- |
| @auto-engineer/narrative | Domain model type definitions |

External:

| Package | Usage |
| ------------------- | --------------------------- |
| @nestjs/cqrs | CQRS command/query pattern |
| @nestjs/graphql | GraphQL schema generation |
| @nestjs/apollo | Apollo Server integration |
| @mikro-orm/core | ORM for entity persistence |
| @mikro-orm/sqlite | SQLite database driver |
| ejs | Template rendering engine |
| prettier | Generated code formatting |
| change-case | Naming convention utilities |
| execa` | Dependency installation |

---

Known Limitations

This generator is experimental. Current limitations include:

- Schema extraction is incomplete for complex slice types
- Generated code may require manual fixes
- Test coverage is minimal
- Only SQLite persistence is supported