old_contents: const {app, BrowserWindow} = require('electron')
  
  // Keep a global reference of the window object, if you don't, the window will
  // be closed automatically when the JavaScript object is garbage collected.
  let mainWindow
  
  function createWindow () {
    mainWindow = new BrowserWindow({width: 1200, height: 600})
    mainWindow.loadURL(`file://${__dirname}/demo/index.html`)
  
    // Open the DevTools.
    mainWindow.webContents.openDevTools()
  
    // Emitted when the window is closed.
    mainWindow.on('closed', function () {
      mainWindow = null
    })
  }
  
  app.on('ready', createWindow)
  
  // 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()
    }
  })
  
  app.on('activate', function () {
    // On OS X it's common to re-create a window in the app when the
    // dock icon is clicked and there are no other windows open.
    if (mainWindow === null) {
      createWindow()
    }
  })
  
new_contents: const electron = require('electron')
  const {app, BrowserWindow} = electron
  
  // Keep a global reference of the window object, if you don't, the window will
  // be closed automatically when the JavaScript object is garbage collected.
  let mainWindow
  
  function createWindow () {
    const {width,  height} = electron.screen.getPrimaryDisplay().workAreaSize
    mainWindow = new BrowserWindow({width, height})
    mainWindow.loadURL(`file://${__dirname}/demo/index.html`)
  
    // Open the DevTools.
    //mainWindow.webContents.openDevTools()
  
    // Emitted when the window is closed.
    mainWindow.on('closed', function () {
      mainWindow = null
    })
  }
  
  app.on('ready', createWindow)
  
  // 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()
    }
  })
  
  app.on('activate', function () {
    // On OS X it's common to re-create a window in the app when the
    // dock icon is clicked and there are no other windows open.
    if (mainWindow === null) {
      createWindow()
    }
  })
  
subject: make default window size = available space