fixed eslint error & integrated with prettier as well as formatted the whole codebase (#3450)

index.js

@@ -4,30 +4,30 @@ const path = require('path')
 
 var error = null
 
-function execMainApp () {
+function execMainApp() {
   const appRootPath = path.join(process.execPath, '../..')
   const updateDotExePath = path.join(appRootPath, 'Update.exe')
   const exeName = path.basename(process.execPath)
 
-  function spawnUpdate (args, cb) {
+  function spawnUpdate(args, cb) {
     var stdout = ''
     var updateProcess = null
     try {
       updateProcess = ChildProcess.spawn(updateDotExePath, args)
     } catch (e) {
-      process.nextTick(function () {
+      process.nextTick(function() {
         cb(e)
       })
     }
 
-    updateProcess.stdout.on('data', function (data) {
+    updateProcess.stdout.on('data', function(data) {
       stdout += data
     })
 
-    updateProcess.on('error', function (_error) {
+    updateProcess.on('error', function(_error) {
       error = _error
     })
-    updateProcess.on('close', function (code, signal) {
+    updateProcess.on('close', function(code, signal) {
       if (code !== 0) {
         error = new Error('Command failed: #{signal ? code}')
         error.code = code
@@ -38,7 +38,7 @@ function execMainApp () {
     })
   }
 
-  var handleStartupEvent = function () {
+  var handleStartupEvent = function() {
     if (process.platform !== 'win32') {
       return false
     }
@@ -46,7 +46,7 @@ function execMainApp () {
     var squirrelCommand = process.argv[1]
     switch (squirrelCommand) {
       case '--squirrel-install':
-        spawnUpdate(['--createShortcut', exeName], function (err) {
+        spawnUpdate(['--createShortcut', exeName], function(err) {
           if (err) console.error(err)
           app.quit()
         })
@@ -55,7 +55,7 @@ function execMainApp () {
         app.quit()
         return true
       case '--squirrel-uninstall':
-        spawnUpdate(['--removeShortcut', exeName], function (err) {
+        spawnUpdate(['--removeShortcut', exeName], function(err) {
           if (err) console.error(err)
           app.quit()
         })