hot reloading of server-side feathersjs application (put this in src/)

watch.js

const logger = require('winston');
const invalidate = require('invalidate-module');
const { resolve } = require('path');
const chokidar = require('chokidar');

process.on('unhandledRejection', (reason, p) => {
  logger.error('Unhandled Rejection at: Promise ', p, reason);
});

const src = (...args) => resolve(__dirname, ...args);

const getApplication = (() => {
  let app = null;

  chokidar
    .watch([src()], {
      ignoreInitial:    true,
      awaitWriteFinish: {
        stabilityThreshold: 200,
        pollInterval:       50,
      },
    })
    .unwatch(src('index.js'))
    .on('all', (evt, filename) => {
      if (filename.endsWith('.js')) {
        logger.info(`reloaded ${filename}`);
        invalidate(resolve(filename));
        app = null;
      }
    });

  return () => {
    if (app === null) {
      app = require('./app');
    }
    return app;
  };
})();

const handler = {
  get(target, name) {
    return target()[name];
  },
  set(target, name, value) {
    target()[name] = value;
  },
  apply(target, that, args) {
    return target().apply(that, args);
  },
};

const proxy = new Proxy(getApplication, handler);

const hostname = getApplication().get('host');
const port = getApplication().get('port');
const server = proxy.listen(port);

server.on('listening', () => {
  logger.info('Feathers application started on http://%s:%d', hostname, port);
});