async.js

const {ipcMain, app, BrowserWindow} = require('electron');

const fs = require('fs');
const fsPromises = fs.promises;
console.log(process.version)

const path = 'd:\\Users\\swt02026\\Desktop\\zcb\\aaa.txt';

var position = 0;

var mainWindow = null;
var isFinishload = false;
var fh = null;
(async () => {
  fh = await fsPromises.open(path, 'r+');
})();


function StartWather() {
  var chokidar = require('chokidar');
  var watcher = chokidar.watch(path, {ignored: /[\/\\]\./, persistent: true});
  watcher.on('change', (path) => {
    console.log(path);
  });
}

// Quit when all windows are closed.
app.on('window-all-closed', function() {
  // On OS X it is common for applications and their menu bar
  // to stay active until the user quits explicitly with Cmd + Q
  if (process.platform != 'darwin') {
    app.quit();
  }
});

// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
app.on('ready', function() {
  // Create the browser window.
  mainWindow = new BrowserWindow({width: 800, height: 600});

  // and load the index.html of the app.
  mainWindow.loadURL('file://' + __dirname + '/index.html');
  mainWindow.webContents.on('did-finish-load', () => {
    var content = null;
    (async () => {
      content = await fh.readFile();
      mainWindow.webContents.send('create', content);
      StartWather();
    })();
    // position += content.length;

    // StartWather();
  });

  // Emitted when the window is closed.
  mainWindow.on('closed', function() {
    // Dereference the window object, usually you would store windows
    // in an array if your app supports multi windows, this is the time
    // when you should delete the corresponding element.
    mainWindow = null;
  });
});