^{Social Media Photo by Omid Kashmari on Unsplash}

A zero dependencies, 100% code covered, inotifywait wrap based on inotify-tools and spawn.

// listen to events via:
// inw.on(INotifyWait.IN_CLOSE, ({type, path, entry}) => {});
class INotifyWait extends EventEmitter {

  constructor(
    path,               // a single path, or a list of paths, each
                        // representing either a file or a folder
    options = {
      exclude: null,    // a RegExp to exclude files (passed as shell argument)
      include: null,    // a RegExp to include files (passed as shell argument)
                        // Please note `include` option requires inotifywait 3.20+
      persistent: true, // keep watching until .stop()
      recursive: false, // recursive within folders
      events: 0         // one or more events to listen for
                        // if omitted, all events are listened
    }
  ) {}

  // kill the subprocess and stop listening to any event
  stop() {}
}

For RegExp properties, use the /*\.txt/i flag to make it case insensitive.

Please read inotifywait man page to know more about the underlying features offered by include and exclude.

In order to run this module in python too, please be sure you have installed the following pip dependency.

sudo pip3 install inotify_simple

Because every other project has either problems compiling code in this or that version of NodeJS, or it's been unmaintained for months or years, with growing amount of bugs.

This project wants to keep it both simple and portable, relying on system inotifywait, avoiding any present or future issue with native/compiled code, making it easy to bring and work with on ARM and other IoT devices too.

Where there is NodeJS, and there is inotifywait, this project might be all you need.

const INotifyWait = require('inotifywait-spawn');
const {IN_CLOSE_WRITE, IN_DELETE, IN_MODIFY} = INotifyWait;

// single file
const inw = new INotifyWait('test.txt', {events: IN_DELETE | IN_CLOSE_WRITE});
inw.on('error', console.error);
inw.on(
  IN_DELETE,
  ({type, path}) => console.log(`${path} removed`)
);
inw.on(
  IN_CLOSE_WRITE,
  ({type, path}) => console.log(`${path} ready to be read`)
);

// folder
const inw = new INotifyWait('.', {recursive: true, events: IN_MODIFY});
inw.on('error', console.error);
inw.on(IN_MODIFY, ({type, path, entry}) => {
  type === IN_MODIFY; // the event type is always available
  console.log(`${entry} modified in ${path}`);
});

// multiple files/folders (still one spawned process only)
const inw = new INotifyWait(
  ['test', 'node_modules', 'build'],
  {recursive: true, events: IN_MODIFY}
);
inw.on('error', console.error);
inw.on(IN_MODIFY, ({type, path, entry}) => {
  console.log(`${entry} modified in ${path}`);
});

Please check test/index.js to see or know more.

Following the list of events supported and available via inotifywait.

These events are better described in the inotify documentation.

• IN_ACCESS, to be notified on file access
• IN_MODIFY, to be notified on changes
• IN_CLOSE_WRITE, to be notified on end writing
• IN_CLOSE_NOWRITE, to be notified on end reading
• IN_OPEN, to be notified on file opened
• IN_MOVED_FROM, to be notified on files moved from
• IN_MOVED_TO, to be notified on files move to
• IN_CREATE, to be notified on files creation (folder)
• IN_DELETE, to be notified on deletion (folder)
• IN_DELETE_SELF, to be notified on deletion of the watched path
• IN_MOVE_SELF, to be notified when watched path is moved
• IN_UNMOUNT, to be notified on patsh unmounted
• IN_CLOSE, to be notified on either IN_CLOSE_WRITE or IN_CLOSE_NOWRITE
• IN_MOVE, to be notified on either IN_MOVED_FROM or IN_MOVED_TO

Fully tested on ArchLinux from NodeJS 6 to latest, this should work with every other Linux distribution that offers inotify-tools and inotifywait with it.

Please note that some options might not be available with older versions of inotifywait, like it is for include in current Ubuntu and inotifywait version < 3.20.