Scripts

To automatically build and run your Fastify server in watch mode, you can use tsc for compilation and nodemon to watch for changes and restart the server automatically. Below are the steps and script commands to set this up.

Step 1: Install Required Development Dependencies

1. Nodemon: A tool that helps with auto-restarting the server whenever file changes in the directory are detected.
2. TypeScript: For compiling .ts files to .js.

Run the following command to install nodemon and TypeScript as development dependencies:

npm install -D nodemon typescript

Step 2: Configure TypeScript for Incremental Builds

Ensure your tsconfig.json is set up for incremental builds by including the outDir option, which specifies where compiled JavaScript files will be placed, and enabling watch mode:

{
  "compilerOptions": {
    "target": "ES2020",
    "module": "commonjs",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "outDir": "./dist",
    "rootDir": "./src"
  },
  "include": ["src/**/*.ts"]
}

Step 3: Update Project Structure

Organize your project with the following structure to maintain clean code separation:

/my-microservice
│
├── /src
│   └── server.ts         # Main server file
│
├── /dist                 # Compiled JavaScript output
├── tsconfig.json         # TypeScript configuration
└── package.json          # Project configuration

Step 4: Add Scripts to package.json

Add the following scripts to your package.json to build, watch, and run the server:

"scripts": {
  "build": "tsc",                                 // Compile TypeScript to JavaScript
  "start": "node dist/server.js",                 // Run the compiled JavaScript server
  "dev": "nodemon --watch 'src/**/*.ts' --exec 'tsc && node dist/server.js'"  // Watch and auto-restart
}

Step 5: Running the Server in Watch Mode

Use the dev script to run the server in auto watch mode:

npm run dev

How the dev Command Works:

1. Nodemon Watches Files: The command watches for changes in any .ts file inside the src folder.

2. Compile and Restart: When a change is detected, nodemon first compiles the TypeScript code using tsc, then runs the compiled JavaScript using NodeJS.

3. Auto-Restart: If any file changes, the server automatically stops and restarts, reflecting the latest changes without requiring manual intervention.

Additional Customization (Optional):

1. Custom nodemon.json: You can create a nodemon.json file to further customize how nodemon behaves:

   {
     "watch": ["src"],
     "ext": "ts",
     "exec": "tsc && node dist/server.js",
     "ignore": ["dist"]
   }

2. Use ts-node: If you prefer not to compile manually every time, you can directly run TypeScript files using ts-node (requires ts-node package):

   npm install -D ts-node

   Modify the dev script to:

   "dev": "nodemon --watch 'src/**/*.ts' --exec 'ts-node src/server.ts'"

This setup will streamline your development workflow, allowing you to focus on coding without needing to manually build and restart the server each time you make a change. Let me know if you need any adjustments or further guidance!