diff --git a/lib/browser/api/dialog.js b/lib/browser/api/dialog.js
index 58800a390ce4..8eb3096b052c 100644
--- a/lib/browser/api/dialog.js
+++ b/lib/browser/api/dialog.js
@@ -4,8 +4,6 @@ const {app, BrowserWindow} = require('electron')
 const binding = process.atomBinding('dialog')
 const v8Util = process.atomBinding('v8_util')
 
-var includes = [].includes
-
 const fileDialogProperties = {
   openFile: 1 << 0,
   openDirectory: 1 << 1,
@@ -14,13 +12,13 @@ const fileDialogProperties = {
   showHiddenFiles: 1 << 4
 }
 
-var messageBoxTypes = ['none', 'info', 'warning', 'error', 'question']
+const messageBoxTypes = ['none', 'info', 'warning', 'error', 'question']
 
-var messageBoxOptions = {
+const messageBoxOptions = {
   noLink: 1 << 0
 }
 
-var parseArgs = function (window, options, callback, ...args) {
+const parseArgs = function (window, options, callback, ...args) {
   if (window !== null && window.constructor !== BrowserWindow) {
     // Shift.
     [callback, options, window] = [options, window, null]
@@ -32,7 +30,7 @@ var parseArgs = function (window, options, callback, ...args) {
   }
 
   // Fallback to using very last argument as the callback function
-  var lastArgument = args[args.length - 1]
+  const lastArgument = args[args.length - 1]
   if ((callback == null) && typeof lastArgument === 'function') {
     callback = lastArgument
   }
@@ -40,7 +38,7 @@ var parseArgs = function (window, options, callback, ...args) {
   return [window, options, callback]
 }
 
-var checkAppInitialized = function () {
+const checkAppInitialized = function () {
   if (!app.isReady()) {
     throw new Error('dialog module can only be used after app is ready')
   }
@@ -48,140 +46,173 @@ var checkAppInitialized = function () {
 
 module.exports = {
   showOpenDialog: function (...args) {
-    var prop, properties, value, wrappedCallback
     checkAppInitialized()
+
     let [window, options, callback] = parseArgs(...args)
+
     if (options == null) {
       options = {
         title: 'Open',
         properties: ['openFile']
       }
     }
-    if (options.properties == null) {
-      options.properties = ['openFile']
+
+    let {buttonLabel, defaultPath, filters, properties, title} = options
+
+    if (properties == null) {
+      properties = ['openFile']
     }
-    if (!Array.isArray(options.properties)) {
+
+    if (!Array.isArray(properties)) {
       throw new TypeError('Properties must be an array')
     }
-    properties = 0
-    for (prop in fileDialogProperties) {
-      value = fileDialogProperties[prop]
-      if (includes.call(options.properties, prop)) {
-        properties |= value
+
+    let dialogProperties = 0
+    for (const prop in fileDialogProperties) {
+      if (properties.includes(prop)) {
+        dialogProperties |= fileDialogProperties[prop]
       }
     }
-    if (options.title == null) {
-      options.title = ''
-    } else if (typeof options.title !== 'string') {
+
+    if (title == null) {
+      title = ''
+    } else if (typeof title !== 'string') {
       throw new TypeError('Title must be a string')
     }
-    if (options.buttonLabel == null) {
-      options.buttonLabel = ''
-    } else if (typeof options.buttonLabel !== 'string') {
+
+    if (buttonLabel == null) {
+      buttonLabel = ''
+    } else if (typeof buttonLabel !== 'string') {
       throw new TypeError('Button label must be a string')
     }
-    if (options.defaultPath == null) {
-      options.defaultPath = ''
-    } else if (typeof options.defaultPath !== 'string') {
+
+    if (defaultPath == null) {
+      defaultPath = ''
+    } else if (typeof defaultPath !== 'string') {
       throw new TypeError('Default path must be a string')
     }
-    if (options.filters == null) {
-      options.filters = []
+
+    if (filters == null) {
+      filters = []
     }
-    wrappedCallback = typeof callback === 'function' ? function (success, result) {
+
+    const wrappedCallback = typeof callback === 'function' ? function (success, result) {
       return callback(success ? result : void 0)
     } : null
-    return binding.showOpenDialog(options.title, options.buttonLabel, options.defaultPath, options.filters, properties, window, wrappedCallback)
+    return binding.showOpenDialog(title, buttonLabel, defaultPath, filters,
+                                  dialogProperties, window, wrappedCallback)
   },
 
   showSaveDialog: function (...args) {
-    var wrappedCallback
     checkAppInitialized()
+
     let [window, options, callback] = parseArgs(...args)
+
     if (options == null) {
       options = {
         title: 'Save'
       }
     }
-    if (options.title == null) {
-      options.title = ''
-    } else if (typeof options.title !== 'string') {
+
+    let {buttonLabel, defaultPath, filters, title} = options
+
+    if (title == null) {
+      title = ''
+    } else if (typeof title !== 'string') {
       throw new TypeError('Title must be a string')
     }
-    if (options.buttonLabel == null) {
-      options.buttonLabel = ''
-    } else if (typeof options.buttonLabel !== 'string') {
+
+    if (buttonLabel == null) {
+      buttonLabel = ''
+    } else if (typeof buttonLabel !== 'string') {
       throw new TypeError('Button label must be a string')
     }
-    if (options.defaultPath == null) {
-      options.defaultPath = ''
-    } else if (typeof options.defaultPath !== 'string') {
+
+    if (defaultPath == null) {
+      defaultPath = ''
+    } else if (typeof defaultPath !== 'string') {
       throw new TypeError('Default path must be a string')
     }
-    if (options.filters == null) {
-      options.filters = []
+
+    if (filters == null) {
+      filters = []
     }
-    wrappedCallback = typeof callback === 'function' ? function (success, result) {
+
+    const wrappedCallback = typeof callback === 'function' ? function (success, result) {
       return callback(success ? result : void 0)
     } : null
-    return binding.showSaveDialog(options.title, options.buttonLabel, options.defaultPath, options.filters, window, wrappedCallback)
+    return binding.showSaveDialog(title, buttonLabel, defaultPath, filters,
+                                  window, wrappedCallback)
   },
 
   showMessageBox: function (...args) {
-    var flags, i, j, len, messageBoxType, ref2, ref3, text
     checkAppInitialized()
+
     let [window, options, callback] = parseArgs(...args)
+
     if (options == null) {
       options = {
         type: 'none'
       }
     }
-    if (options.type == null) {
-      options.type = 'none'
+
+    let {buttons, cancelId, defaultId, detail, icon, message, title, type} = options
+
+    if (type == null) {
+      type = 'none'
     }
-    messageBoxType = messageBoxTypes.indexOf(options.type)
-    if (!(messageBoxType > -1)) {
+
+    const messageBoxType = messageBoxTypes.indexOf(type)
+    if (messageBoxType === -1) {
       throw new TypeError('Invalid message box type')
     }
-    if (!Array.isArray(options.buttons)) {
+
+    if (!Array.isArray(buttons)) {
       throw new TypeError('Buttons must be an array')
     }
-    if (options.title == null) {
-      options.title = ''
-    } else if (typeof options.title !== 'string') {
+
+    if (title == null) {
+      title = ''
+    } else if (typeof title !== 'string') {
       throw new TypeError('Title must be a string')
     }
-    if (options.message == null) {
-      options.message = ''
-    } else if (typeof options.message !== 'string') {
+
+    if (message == null) {
+      message = ''
+    } else if (typeof message !== 'string') {
       throw new TypeError('Message must be a string')
     }
-    if (options.detail == null) {
-      options.detail = ''
-    } else if (typeof options.detail !== 'string') {
+
+    if (detail == null) {
+      detail = ''
+    } else if (typeof detail !== 'string') {
       throw new TypeError('Detail must be a string')
     }
-    if (options.icon == null) {
-      options.icon = null
+
+    if (icon == null) {
+      icon = null
     }
-    if (options.defaultId == null) {
-      options.defaultId = -1
+
+    if (defaultId == null) {
+      defaultId = -1
     }
 
     // Choose a default button to get selected when dialog is cancelled.
-    if (options.cancelId == null) {
-      options.cancelId = 0
-      ref2 = options.buttons
-      for (i = j = 0, len = ref2.length; j < len; i = ++j) {
-        text = ref2[i]
-        if ((ref3 = text.toLowerCase()) === 'cancel' || ref3 === 'no') {
-          options.cancelId = i
+    if (cancelId == null) {
+      cancelId = 0
+      for (let i = 0; i < buttons.length; i++) {
+        const text = buttons[i].toLowerCase()
+        if (text === 'cancel' || text === 'no') {
+          cancelId = i
           break
         }
       }
     }
-    flags = options.noLink ? messageBoxOptions.noLink : 0
-    return binding.showMessageBox(messageBoxType, options.buttons, options.defaultId, options.cancelId, flags, options.title, options.message, options.detail, options.icon, window, callback)
+
+    const flags = options.noLink ? messageBoxOptions.noLink : 0
+    return binding.showMessageBox(messageBoxType, buttons, defaultId, cancelId,
+                                  flags, title, message, detail, icon, window,
+                                  callback)
   },
 
   showErrorBox: function (...args) {
@@ -190,9 +221,6 @@ module.exports = {
 }
 
 // Mark standard asynchronous functions.
-var ref1 = ['showMessageBox', 'showOpenDialog', 'showSaveDialog']
-var j, len, api
-for (j = 0, len = ref1.length; j < len; j++) {
-  api = ref1[j]
-  v8Util.setHiddenValue(module.exports[api], 'asynchronous', true)
-}
+v8Util.setHiddenValue(module.exports.showMessageBox, 'asynchronous', true)
+v8Util.setHiddenValue(module.exports.showOpenDialog, 'asynchronous', true)
+v8Util.setHiddenValue(module.exports.showSaveDialog, 'asynchronous', true)