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tessl/npm-sveltejs--adapter-node

Adapter for SvelteKit apps that generates a standalone Node server

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@sveltejs/adapter-node

@sveltejs/adapter-node is a SvelteKit adapter that generates a standalone Node.js server for SvelteKit applications. It transforms SvelteKit apps into production-ready Node server builds with support for server-side rendering, API routes, static asset serving, and comprehensive environment configuration.

Package Information

  • Package Name: @sveltejs/adapter-node
  • Package Type: npm
  • Language: JavaScript/TypeScript
  • Installation: npm install @sveltejs/adapter-node

Core Imports

import adapter from '@sveltejs/adapter-node';

For CommonJS:

const adapter = require('@sveltejs/adapter-node');

Basic Usage

// svelte.config.js
import adapter from '@sveltejs/adapter-node';

/** @type {import('@sveltejs/kit').Config} */
const config = {
  kit: {
    adapter: adapter()
  }
};

export default config;

With configuration options:

// svelte.config.js  
import adapter from '@sveltejs/adapter-node';

/** @type {import('@sveltejs/kit').Config} */
const config = {
  kit: {
    adapter: adapter({
      out: 'build',
      precompress: true,
      envPrefix: 'MY_CUSTOM_'
    })
  }
};

export default config;

Architecture

The adapter works by:

  1. Build Process: Transforms SvelteKit app into standalone Node.js server
  2. Asset Handling: Generates optimized client assets with optional compression
  3. Server Generation: Creates Node.js server with request handler and lifecycle management
  4. Environment Configuration: Supports extensive environment variable customization
  5. Production Deployment: Outputs production-ready server that can run independently

The generated server includes:

  • Static asset serving with caching headers
  • Server-side rendering (SSR) with SvelteKit integration
  • Prerendered route handling
  • Graceful shutdown and socket activation support
  • Configurable security headers and reverse proxy support

Capabilities

Adapter Factory Function

Creates and configures the SvelteKit adapter with optional settings.

/**
 * Creates a SvelteKit adapter for Node.js deployment
 * @param options - Configuration options for the adapter
 * @returns Configured SvelteKit adapter
 */
export default function adapter(options?: AdapterOptions): Adapter;

interface AdapterOptions {
  /** Output directory for the generated server (default: 'build') */
  out?: string;
  /** Enable gzip/brotli compression of static assets (default: true) */
  precompress?: boolean;
  /** Prefix for environment variables (default: '') */
  envPrefix?: string;
}

interface Adapter {
  name: string;
  adapt(builder: Builder): Promise<void>;
  supports: {
    read(): boolean;
    instrumentation(): boolean;
  };
}

interface Builder {
  log: { minor(message: string): void };
  rimraf(path: string): void;
  mkdirp(path: string): void;
  config: { kit: { paths: { base: string } } };
  prerendered: { paths: string[] };
  getBuildDirectory(name: string): string;
  writeClient(dest: string): void;
  writePrerendered(dest: string): void;
  writeServer(dest: string): void;
  generateManifest(options: { relativePath: string }): string;
  compress(path: string): Promise<void>;
  copy(from: string, to: string, options?: { replace?: Record<string, string> }): void;
  hasServerInstrumentationFile?(): boolean;
  instrument?(options: { entrypoint: string; instrumentation: string; module: { exports: string[] } }): void;
}

Generated Server Environment Variables

The generated server supports extensive environment variable configuration:

Core Server Configuration

// Server binding configuration
SOCKET_PATH?: string;        // Unix socket path (alternative to HOST/PORT)
HOST?: string;              // Server host (default: '0.0.0.0') 
PORT?: string;              // Server port (default: '3000')

// Server lifecycle
SHUTDOWN_TIMEOUT?: string;   // Graceful shutdown timeout in seconds (default: '30')
IDLE_TIMEOUT?: string;      // Idle timeout for socket activation (default: '0')

// Socket activation (systemd)
LISTEN_PID?: string;        // Process ID for socket activation
LISTEN_FDS?: string;        // Number of file descriptors for socket activation

Request Handling Configuration

// Origin and URL configuration
ORIGIN?: string;            // Override automatic origin detection
BODY_SIZE_LIMIT?: string;   // Request body size limit (default: '512K')

// Reverse proxy headers
XFF_DEPTH?: string;         // X-Forwarded-For header depth (default: '1')
ADDRESS_HEADER?: string;    // Custom client address header name
PROTOCOL_HEADER?: string;   // Custom protocol header name  
HOST_HEADER?: string;       // Custom host header name
PORT_HEADER?: string;       // Custom port header name

All environment variables (except LISTEN_PID and LISTEN_FDS) can be prefixed using the envPrefix option.

Type Definitions

Global platform interface extension for accessing Node.js request object.

declare global {
  namespace App {
    interface Platform {
      /** The original Node.js HTTP request object */
      req: import('node:http').IncomingMessage;
    }
  }
}

Deployment

After building with the adapter, the generated server can be started with:

node build/index.js

The server will log its binding information and accept requests on the configured host and port.

Environment Variable Examples

# Basic configuration
HOST=127.0.0.1 PORT=8080 node build/index.js

# With custom prefix
MY_APP_HOST=127.0.0.1 MY_APP_PORT=8080 node build/index.js

# With reverse proxy headers
ADDRESS_HEADER=x-real-ip PROTOCOL_HEADER=x-forwarded-proto node build/index.js

# With body size limit
BODY_SIZE_LIMIT=1M node build/index.js

# Unix socket
SOCKET_PATH=/tmp/app.sock node build/index.js

Graceful Shutdown

The generated server supports graceful shutdown via SIGTERM and SIGINT signals, with configurable timeout:

# Custom shutdown timeout (60 seconds)
SHUTDOWN_TIMEOUT=60 node build/index.js

Socket Activation

For systemd socket activation:

# Systemd will set these automatically
LISTEN_PID=1234 LISTEN_FDS=1 node build/index.js

docs

index.md

tile.json