nodemon

What is nodemon?

Nodemon is a utility that monitors for any changes in your source code and automatically restarts your server. It is mainly used during the development of Node.js applications to increase productivity by reducing the need to manually restart the server after making code changes.

What are nodemon's main functionalities?

Automatic Restart

Automatically restarts the node application when file changes in the directory are detected. To use nodemon, replace the word 'node' on the command line when executing your script.

nodemon app.js

Custom Watch List

Tells nodemon to only restart if there are changes in the 'app' or 'libs' directories. You can specify multiple directories to watch.

nodemon --watch app --watch libs app/server.js

Delay Restart

Delays the restart upon changes for a specified amount of time (in seconds). This can be useful if you're waiting for a compilation of files to complete before restarting.

nodemon --delay 10 app/server.js

Script Configuration

Allows you to configure nodemon as a script in your package.json file, enabling you to start your application with 'npm start'.

{\n  \"scripts\": {\n    \"start\": \"nodemon app.js\"\n  }\n}

Ignore Specific Files

Prevents nodemon from restarting when changes are made to specific files. Useful when you don't want to trigger a restart for changes in non-relevant files.

nodemon --ignore 'app/ignore.js'

Other packages similar to nodemon

pm2

PM2 is a production process manager for Node.js applications with a built-in load balancer. It differs from nodemon in that it's designed for production use, offering features like clustering, daemonizing, and log management.

forever

Forever is a simple CLI tool for ensuring that a given script runs continuously (i.e., forever). It's more similar to pm2 and is often used in production environments, unlike nodemon which is typically used in development.

supervisor

Supervisor is a nodemon-like tool that restarts programs when file changes in the directory are detected. It is less feature-rich than nodemon and is primarily used for running and debugging during development.

node-dev

Node-dev is another development tool that automatically restarts your node application when files are modified. It is similar to nodemon but with fewer configuration options.

README

nodemon

For use during development of a node.js based application.

nodemon will watch all the files in the directory that nodemon was started, and if they change, it will automatically restart your node application.

nodemon does not require any changes to your code or method of development. nodemon simply wraps your node application and keeps an eye on any files that have changed.

Installation

Either through forking or:

npm install nodemon

And nodemon will be installed in to your bin path.

Usage

nodemon wraps your application, so you can pass all the arguments you would normally pass to your app:

nodemon [your node app]

For example, if my application accepted a host and port as the arguments, I would start it as so:

nodemon ./server.js localhost 8080

Any output from this script is prefixed with [nodemon], otherwise all output from your application, errors included, will be echoed out as expected.

Ignoring files

In some cases you will want to ignore some specific files, directories or file patterns, to prevent nodemon from prematurely restarting your application.

The nodemon-ignore file is automatically created in the directory that you run your application from, so that you can have application specific ignore lists.

You can use the example ignore file as a basis for your nodemon, but it's very simple to create your own:

# this is my ignore file with a nice comment at the top

/vendor/*     # ignore all external submodules
/public/*     # static files
./README.md   # a specific file
*.css         # ignore any CSS files too

The ignore file accepts:

• Comments starting with a # symbol
• Blank lines
• Specific files
• File patterns (this is converted to a regex, so you have full control of the pattern)

Prerequisites

nodemon currently depends on the unix find command (which also is installed on Macs)