Dev Command

Overview

The dev command starts your Dwex application in development mode with hot reload. It automatically restarts your server when files change, clearing the console and showing restart timing for a smooth development experience.

Usage

bunx dwex dev

Features

• Hot Reload - Automatically restarts on file changes
• Clear Console - Clean output on each restart
• Timing Info - Shows startup and restart duration
• Port Configuration - Customize server port
• Colorful Output - Clear status messages with colors

Options

-p, --port <port>

Specify a custom port:

bunx dwex dev --port 9929
bunx dwex dev -p 4000

How It Works

The dev command:

1. Reads entry point from index.ts (or config)
2. Starts your app with Bun's --watch flag
3. Monitors file changes in your project
4. Clears console and restarts on changes
5. Shows timing information for each restart

Output

On first start:

ℹ Starting Dwex development server...

✔ Server ready in 245ms

  ➜  Local:   http://localhost:9929
  ➜  Watching for changes...

On file change:

ℹ File change detected, restarting...

✔ Server restarted in 123ms
  ➜  Local:   http://localhost:9929

Environment Variables

Set environment variables for development:

PORT=8080 bunx dwex dev

Or create a .env file:

PORT=9929
NODE_ENV=development
DATABASE_URL=postgresql://localhost/mydb

Configuration

Customize dev server in dwex.config.ts:

export default {
  entry: "index.ts",
  port: 9929,
};

See Configuration for all options.

Watching Files

The dev server uses Bun's native --watch flag, which watches:

• All TypeScript/JavaScript files
• JSON configuration files
• Files imported by your application

Files not watched:

• node_modules/
• dist/ or build output
• .git/
• Files in .gitignore

Performance

Development mode is optimized for fast restarts:

• Initial start: ~200-500ms
• Hot restarts: ~100-300ms
• No build step required (uses Bun's JIT)

Tips for Development

Fast Restarts

Keep restart times fast by:

1. Using lazy imports for heavy modules
2. Avoiding expensive initialization logic
3. Using environment-based conditional imports

// Lazy load heavy modules
if (process.env.NODE_ENV === "development") {
  const { devTool } = await import("./dev-tools");
}

Multiple Instances

Run multiple apps on different ports:

# Terminal 1
bunx dwex dev --port 9929

# Terminal 2
bunx dwex dev --port 4000

Debug Mode

Enable verbose logging:

import "reflect-metadata";
import { DwexFactory } from "@dwex/core";
import { RootModule } from "./root.module";

const app = await DwexFactory.create(RootModule, {
  logger: ["log", "error", "warn", "debug", "verbose"],
});

await app.listen(9929);

Graceful Shutdown

The dev server handles shutdown gracefully:

• Press Ctrl+C to stop
• Server closes active connections
• Process exits cleanly

Troubleshooting

Port Already in Use

If port is already taken:

bunx dwex dev --port 9929

Or find and kill the process:

# macOS/Linux
lsof -ti:9929 | xargs kill -9

# Or use a different port in config

Changes Not Detected

If hot reload isn't working:

1. Ensure files are in the project directory
2. Check file isn't in .gitignore
3. Restart the dev server manually

Slow Restarts

If restarts are slow:

1. Check for heavy synchronous operations during app initialization
2. Use lazy imports for large dependencies
3. Profile startup with console.time()

console.time("startup");
const app = await DwexFactory.create(RootModule);
console.timeEnd("startup");

Comparison with Production

Next Steps

• Build Command - Create production builds
• Generate Command - Scaffold code quickly
• Configuration - Customize dev server