@pegasus-heavy/nestjs-platform-deno

A NestJS HTTP adapter for the Deno runtime, similar to @nestjs/platform-express and @nestjs/platform-fastify.

This adapter allows you to run your NestJS applications directly on Deno's native HTTP server (Deno.serve) without requiring Express, Fastify, or any other Node.js HTTP framework.

Features

• 🦕 Native Deno HTTP server support via Deno.serve
• 🚀 Full NestJS compatibility
• 📦 Zero external HTTP framework dependencies
• 🔒 Built-in CORS support
• 📁 Static file serving
• 🔄 Middleware support
• 💪 TypeScript first

Installation

# Using Deno
deno add jsr:@pegasus-heavy/nestjs-platform-deno npm:@nestjs/common npm:@nestjs/core

# Using npm/pnpm (for Node.js + Deno interop)
pnpm add @pegasus-heavy/nestjs-platform-deno @nestjs/common @nestjs/core

Usage

Basic Usage

import { NestFactory } from '@nestjs/core';
import { DenoAdapter } from '@pegasus-heavy/nestjs-platform-deno';
import { AppModule } from './app.module.ts';

async function bootstrap() {
  const app = await NestFactory.create(AppModule, new DenoAdapter());
  await app.listen(3000);
}

bootstrap();

With CORS

import { NestFactory } from '@nestjs/core';
import { DenoAdapter } from '@pegasus-heavy/nestjs-platform-deno';
import { AppModule } from './app.module.ts';

async function bootstrap() {
  const app = await NestFactory.create(AppModule, new DenoAdapter());

  app.enableCors({
    origin: ['http://localhost:3000', 'https://myapp.com'],
    methods: 'GET,HEAD,PUT,PATCH,POST,DELETE',
    credentials: true,
  });

  await app.listen(3000);
}

bootstrap();

Serving Static Assets

import { NestFactory } from '@nestjs/core';
import { DenoAdapter } from '@pegasus-heavy/nestjs-platform-deno';
import { AppModule } from './app.module.ts';

async function bootstrap() {
  const app = await NestFactory.create(AppModule, new DenoAdapter());

  const adapter = app.getHttpAdapter() as DenoAdapter;
  adapter.useStaticAssets('./public', {
    prefix: '/static',
    maxAge: 3600,
  });

  await app.listen(3000);
}

bootstrap();

Custom Error Handler

import { NestFactory } from '@nestjs/core';
import { DenoAdapter } from '@pegasus-heavy/nestjs-platform-deno';
import { AppModule } from './app.module.ts';

async function bootstrap() {
  const app = await NestFactory.create(AppModule, new DenoAdapter());

  const adapter = app.getHttpAdapter() as DenoAdapter;
  adapter.setErrorHandler((error, req, res) => {
    console.error('Error:', error);
    res.status(500).json({
      statusCode: 500,
      message: 'Something went wrong',
      timestamp: new Date().toISOString(),
    });
  });

  await app.listen(3000);
}

bootstrap();

Using Express Middleware

The Deno adapter provides full compatibility with Express middleware, allowing you to use the vast ecosystem of existing Express middleware packages.

import { NestFactory } from '@nestjs/core';
import { DenoAdapter } from '@pegasus-heavy/nestjs-platform-deno';
import { AppModule } from './app.module.ts';
import helmet from 'helmet';
import compression from 'compression';
import morgan from 'morgan';

async function bootstrap() {
  const adapter = new DenoAdapter();

  // Use Express middleware directly
  adapter.useExpressMiddleware(helmet());
  adapter.useExpressMiddleware(compression());
  adapter.useExpressMiddleware(morgan('combined'));

  // Apply middleware to specific paths
  adapter.useExpressMiddleware('/api', someApiMiddleware());

  const app = await NestFactory.create(AppModule, adapter);
  await app.listen(3000);
}

bootstrap();

Using Express-style App Object

For middleware that requires an Express app instance (like express-session), you can use getExpressApp():

import { NestFactory } from '@nestjs/core';
import { DenoAdapter } from '@pegasus-heavy/nestjs-platform-deno';
import { AppModule } from './app.module.ts';
import session from 'express-session';
import cookieParser from 'cookie-parser';

async function bootstrap() {
  const adapter = new DenoAdapter();

  // Get an Express-like app interface
  const expressApp = adapter.getExpressApp();

  // Use with middleware that needs app.use()
  expressApp.use(cookieParser());
  expressApp.use(session({
    secret: 'my-secret',
    resave: false,
    saveUninitialized: false,
  }));

  const app = await NestFactory.create(AppModule, adapter);
  await app.listen(3000);
}

bootstrap();

Using Fastify Middleware/Hooks

The Deno adapter also supports Fastify-style hooks and plugins:

import { NestFactory } from '@nestjs/core';
import { DenoAdapter } from '@pegasus-heavy/nestjs-platform-deno';
import { AppModule } from './app.module.ts';

async function bootstrap() {
  const adapter = new DenoAdapter();

  // Use Fastify hooks directly
  adapter.useFastifyHook('onRequest', async (request, reply) => {
    console.log('Request:', request.method, request.url);
  });

  adapter.useFastifyHook('preHandler', (request, reply, done) => {
    // Validate something
    done();
  });

  const app = await NestFactory.create(AppModule, adapter);
  await app.listen(3000);
}

bootstrap();

Using Fastify Plugins

For Fastify plugins that require a Fastify instance:

import { NestFactory } from '@nestjs/core';
import { DenoAdapter } from '@pegasus-heavy/nestjs-platform-deno';
import { AppModule } from './app.module.ts';
import fastifyCors from '@fastify/cors';
import fastifyHelmet from '@fastify/helmet';

async function bootstrap() {
  const adapter = new DenoAdapter();

  // Register Fastify plugins
  await adapter.registerFastifyPlugin(fastifyCors, { origin: '*' });
  await adapter.registerFastifyPlugin(fastifyHelmet);

  // Or use the Fastify instance directly
  const fastify = adapter.getFastifyInstance();

  fastify.addHook('onRequest', async (request, reply) => {
    request.startTime = Date.now();
  });

  fastify.decorateRequest('user', null);

  const app = await NestFactory.create(AppModule, adapter);
  await app.listen(3000);
}

bootstrap();

API Reference

DenoAdapter

The main adapter class that extends NestJS's AbstractHttpAdapter.

Constructor

new DenoAdapter(instance?: unknown)

Static Methods

• DenoAdapter.create(options?: NestApplicationOptions): DenoAdapter - Factory method to create a new adapter instance

Instance Methods

• listen(port: number, callback?: () => void): Promise<void> - Start the server
• listen(port: number, hostname: string, callback?: () => void): Promise<void> - Start the server on a specific hostname
• close(): Promise<void> - Gracefully shutdown the server
• enableCors(options?: DenoCorsOptions): void - Enable CORS
• useStaticAssets(path: string, options?: DenoStaticAssetsOptions): void - Serve static files
• useExpressMiddleware(middleware: ExpressMiddleware): void - Use Express middleware
• useExpressMiddleware(path: string, middleware: ExpressMiddleware): void - Use Express middleware for a path
• getExpressApp(): ExpressLikeApp - Get an Express-compatible app object for middleware
• useFastifyHook(name: FastifyHookName, hook: FastifyHook): void - Use a Fastify hook
• registerFastifyPlugin(plugin, opts?): Promise<void> - Register a Fastify plugin
• getFastifyInstance(): FastifyLikeInstance - Get a Fastify-compatible instance
• setErrorHandler(handler: Function): void - Set custom error handler
• setNotFoundHandler(handler: Function): void - Set custom 404 handler
• getHttpServer(): DenoHttpServer | undefined - Get the underlying Deno server
• getType(): string - Returns 'deno'

DenoCorsOptions

interface DenoCorsOptions {
  origin?: string | string[] | boolean | ((origin: string) => boolean | string);
  methods?: string | string[];
  allowedHeaders?: string | string[];
  exposedHeaders?: string | string[];
  credentials?: boolean;
  maxAge?: number;
  preflightContinue?: boolean;
  optionsSuccessStatus?: number;
}

DenoStaticAssetsOptions

interface DenoStaticAssetsOptions {
  prefix?: string;
  index?: string | boolean;
  redirect?: boolean;
  maxAge?: number;
  immutable?: boolean;
  dotfiles?: 'allow' | 'deny' | 'ignore';
  etag?: boolean;
  lastModified?: boolean;
}

Requirements

• Deno 1.40+ (for Deno.serve API)
• NestJS 10.0.0+ or 11.0.0+

Compatibility

This adapter is designed to be a drop-in replacement for the Express or Fastify adapters. Most NestJS features work out of the box:

• ✅ Controllers and routing
• ✅ Dependency injection
• ✅ Middleware (native + Express + Fastify)
• ✅ Express middleware compatibility (helmet, compression, morgan, etc.)
• ✅ Fastify hooks and plugins (@fastify/cors, @fastify/helmet, etc.)
• ✅ Guards
• ✅ Interceptors
• ✅ Pipes
• ✅ Exception filters
• ✅ CORS
• ✅ Static file serving
• ✅ Cookie handling
• ✅ Request/Reply decorators (Fastify-style)
• ⚠️ View engines (not implemented in base adapter)
• ⚠️ WebSockets (requires separate adapter)

License

MIT © Pegasus Heavy Industries LLC