very simple live reload

inject.js

// <![CDATA[  <-- For SVG support
if ('WebSocket' in window) {
  (function () {
    function refreshCSS () {
      var sheets = [].slice.call(document.getElementsByTagName("link"));
      var head = document.getElementsByTagName("head")[0];
      for (var i = 0; i < sheets.length; ++i) {
        var elem = sheets[i];
        head.removeChild(elem);
        var rel = elem.rel;
        if (elem.href && typeof rel != "string" || rel.length == 0 || rel.toLowerCase() == "stylesheet") {
          var url = elem.href.replace(/(&|\?)_cacheOverride=\d+/, '');
          elem.href = url + (url.indexOf('?') >= 0 ? '&' : '?') + '_cacheOverride=' + (new Date().valueOf());
        }
        head.appendChild(elem);
      }
    }
    // var protocol = window.location.protocol === 'http:' ? 'ws://' : 'wss://';
    var address = /* protocol + window.location.host + window.location.pathname */ 'ws://localhost:33314/ws';
    var socket = new WebSocket(address);
    socket.onmessage = function (msg) {
      if (msg.data == 'reload') window.location.reload();
      else if (msg.data == 'refreshcss') refreshCSS();
    };
    console.log('Live reload enabled.');
  })();
}
	// ]]>

package.json

{
  "name": "auto-refresh",
  "version": "1.0.0",
  "description": "",
  "main": "inject.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "chokidar": "^3.0.1",
    "ws": "^7.0.1"
  }
}

ws.js

const chokidar = require('chokidar')
const ws = require('ws')
const wss = new ws.Server({
  port: 33314,
  path: '/ws'
})
wss.on('connection', (w) => {
  chokidar.watch('.', { ignored: /(^|[\/\\])\../ })
    .on('change', (path) => {
      if (!!~path.indexOf('.html')) {
        w.send('reload')
      }
    })
})