@workflow/nest

NestJS integration for Workflow DevKit.

Installation

npm install @workflow/nest
# or
pnpm add @workflow/nest

You also need to install the SWC packages required by NestJS's SWC builder:

npm install -D @swc/cli @swc/core
# or
pnpm add -D @swc/cli @swc/core

Quick Start

1. Initialize SWC Configuration

After installing the package, run the init command to generate the SWC configuration:

npx @workflow/nest init

This creates a .swcrc file configured with the Workflow SWC plugin for client-mode transformations.

Important: Add .swcrc to your .gitignore as it contains machine-specific absolute paths:

echo '/.swcrc' >> .gitignore

2. Configure NestJS to use SWC

Ensure your nest-cli.json has SWC as the builder:

{/@skip-typecheck: Shows nest-cli.json configuration/}

{
  "compilerOptions": {
    "builder": "swc"
  }
}

3. Import the WorkflowModule

In your app.module.ts:

{/@skip-typecheck: Shows WorkflowModule import/}

import { Module } from '@nestjs/common';
import { WorkflowModule } from '@workflow/nest';

@Module({
  imports: [WorkflowModule.forRoot()],
})
export class AppModule {}

4. Create Workflow Files

Create workflow files in your src/ directory with "use workflow" and "use step" directives:

{/@skip-typecheck: Shows workflow file/}

// src/workflows/example.ts
export async function myStep(data: string) {
  'use step';
  return data.toUpperCase();
}

export async function myWorkflow(input: string) {
  'use workflow';
  const result = await myStep(input);
  return result;
}

5. Add Pre-build Scripts

Add scripts to regenerate configuration before builds:

{
  "scripts": {
    "prebuild": "npx @workflow/nest init --force",
    "build": "nest build"
  }
}

Configuration Options

{/@skip-typecheck: Shows WorkflowModule.forRoot options/}

WorkflowModule.forRoot({
  // Directory to scan for workflow files (default: ['src'])
  dirs: ['src'],

  // Output directory for generated bundles (default: '.nestjs/workflow')
  outDir: '.nestjs/workflow',

  // Skip building in production when bundles are pre-built
  skipBuild: false,
});

How It Works

The @workflow/nest package provides:

1. WorkflowModule - A NestJS module that handles workflow bundle building and HTTP routing
2. WorkflowController - Handles workflow and step execution requests at .well-known/workflow/v1/
3. NestLocalBuilder - Builds workflow bundles (steps.mjs, workflows.mjs) from your source files
4. CLI - Generates .swcrc configuration with the SWC plugin properly resolved

Why the CLI?

NestJS uses its own SWC builder that reads configuration from .swcrc. The Workflow SWC plugin needs to be referenced by path in this file. The CLI resolves the plugin path from @workflow/nest's dependencies, eliminating the need for manual configuration or pnpm hoisting.

Technical Details

When you run npx @workflow/nest init, it:

1. Resolves the path to @workflow/swc-plugin (bundled as a dependency of @workflow/nest)
2. Generates .swcrc with the absolute path to the plugin
3. Configures client-mode transformation for workflow files

This approach ensures:

• No manual SWC plugin configuration required
• No pnpm hoisting configuration required in .npmrc
• The plugin is always resolved from the correct location

Why Workflows Must Be in src/

NestJS's SWC builder only compiles files within the sourceRoot directory (typically src/). For the workflow client-mode transform to work, workflow files must be in src/ so they get compiled with the SWC plugin that attaches workflowId properties needed by start().

API Reference

WorkflowModule

{/@skip-typecheck: Shows WorkflowModule usage/}

import { WorkflowModule } from '@workflow/nest';

// Basic usage
WorkflowModule.forRoot()

// With options
WorkflowModule.forRoot({
  dirs: ['src/workflows'],
  outDir: '.nestjs/workflow',
  skipBuild: process.env.NODE_ENV === 'production',
})

CLI Commands

# Generate .swcrc configuration
npx @workflow/nest init

# Force regenerate (overwrites existing)
npx @workflow/nest init --force

# Show help
npx @workflow/nest --help

License

Apache-2.0