Use shared instance of Serial in menu handler

Author: sebromero

backend/ipc.js

@@ -1,6 +1,5 @@
 const fs = require('fs')
-const Serial = require('./serial.js')
-let serial
+const serial = require('./serial.js').sharedInstance
 
 const {
   openFolderDialog,
@@ -10,7 +9,7 @@ const {
 } = require('./helpers.js')
 
 module.exports = function registerIPCHandlers(win, ipcMain, app, dialog) {
-  serial = new Serial(win)
+  serial.win = win // Required to send callback messages to renderer
 
   ipcMain.handle('open-folder', async (event) => {
     console.log('ipcMain', 'open-folder')

backend/menu.js

@@ -1,6 +1,6 @@
 const { app, Menu } = require('electron')
 const path = require('path')
-const Serial = require('./serial.js')
+const serial = require('./serial.js').sharedInstance
 const openAboutWindow = require('about-window').default
 
 module.exports = function registerMenu(win, state = {}) {
@@ -92,7 +92,7 @@ module.exports = function registerMenu(win, state = {}) {
           accelerator: '',
           click: async () => {
             try {
-              await Serial.disconnect()
+              await serial.disconnect()
               win.reload()
             } catch(e) {
               console.error('Reload from menu failed:', e)

backend/serial.js

@@ -1,7 +1,7 @@
 const MicroPython = require('micropython.js')
 
 class Serial {
-    constructor(win) {
+    constructor(win = null) {
         this.win = win
         this.board = new MicroPython()
         this.board.chunk_size = 192
@@ -110,4 +110,6 @@ except OSError:
     }
 }
 
-module.exports = Serial
+const sharedInstance = new Serial()
+
+module.exports = {sharedInstance, Serial}