In addition to letting you write command-line JavaScript programs, Node gives you a way to orchestrate your workflow as you develop these programs. It is a powerful feature that you should take advantage of. To see how this works, you will add a bit of automation to your project.

Take running your server, for example. Every time you want to try something new in your code, you have to repeat a few steps:

You could write a program to automate the work of restarting your service. You are in luck, though – someone has already written it for you, in a module called nodemon. Integrating nodemon into your workflow early on will make writing your program a much smoother experience.

In the terminal, stop your program and run the following command to install the nodemon module:

npm install --save-dev nodemon

You will see the lines below, in which npm is warning you about some blank fields in your package.json file. Do not be alarmed – just be aware that npm is a stickler for details.

npm WARN [email protected] No description
npm WARN [email protected] No repository field.

Notice the --save-dev option that you used in this npm install command. It tells npm to help you keep a list of any third-party modules your application depends on. That list is stored in your package.json file. If necessary, all of the dependencies in that list can be installed by running the npm install command (with no arguments). This means that when you are sharing your code you do not need to include all of the third-party modules as well.

If you look in your package.json file, you will see that npm created a new "devDependencies" section for you, with an entry for nodemon.

...
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "nodemon": "^1.9.1"
  }

Now, update your package.json to add another item to the "scripts" section:

...
"scripts": {
  "test": "echo "Error: no test specified" && exit 1",
  "start": "node index.js",
  "dev": "nodemon index.js"
},
...

In the terminal, restart your node program via your new npm script using the command npm run dev. Note that the command is not simply npm dev. This differs from npm start in that npm assumes that certain commands (like start) will exist. For custom npm scripts, you must specify that you want to run them.

You should see that nodemon is now managing your node program (Figure 15.9).

Figure 15.9  Running via npm run dev

In index.js, change "Hello, World" to "Hello, World!!" and save the changes. nodemon notices and restarts your node program automatically (Figure 15.10).

Figure 15.10  nodemon restarts when your code changes

As you continue to work with node and npm in the following chapters, you will periodically pull in a new module to help out.