Tiny Watcher

tinyWatcher.js

/**
 * Uses fs.watchFile and cluster to watch, fork, and "restart"
 * the file that this code is included in. Run this code before
 * anything else in the script and it will restart a persistent-
 * running fork of itself when the source is modified.
 */

const fs = require('fs')
const cluster = require('cluster')

if (cluster.isMaster) {
  const workerFactory = () => cluster.fork()

  console.log('Forking child process of self...')

  let forked = workerFactory()
  
  fs.watchFile(module.filename, { interval: 150 }, (curr, prev) => {
    if (curr.mtime !== prev.mtime) {
      console.log('Killing child process of self and restarting...')
      forked.kill()
      forked = workerFactory()
    }
  })

  return
}