embed hotkey, config to preferences modal & fix datasaving sequence(Async, Queue)

lib/config.js

@@ -0,0 +1,53 @@
+const electron = require('electron')
+const app = electron.app
+const ipc = electron.ipcMain
+const jetpack = require('fs-jetpack')
+const mainWindow = require('./main-window')
+
+const defaultConfig = {
+  'editor-font-size': '14',
+  'editor-font-family': 'Monaco, Ubuntu Mono, Consolas, source-code-pro, monospace',
+  'editor-indent-type': 'space',
+  'editor-indent-size': '4',
+  'preview-font-size': '14',
+  'preview-font-family': 'Lato, helvetica, arial, sans-serif',
+  'disable-direct-write': false
+}
+const configFile = 'config.json'
+
+var userDataPath = app.getPath('userData')
+
+function getConfig () {
+  var userDataPath = app.getPath('userData')
+  if (jetpack.cwd(userDataPath).exists(configFile)) {
+    try {
+      return JSON.parse(jetpack.cwd(userDataPath).read(configFile, 'utf-8'))
+    } catch (err) {}
+  }
+  return {}
+}
+
+function saveConfig () {
+  var content
+  try {
+    content = JSON.stringify(global.config)
+  } catch (e) {
+    global.config = {}
+    content = JSON.stringify(global.config)
+  }
+  jetpack.cwd(userDataPath).file(configFile, { content })
+}
+
+// Init
+global.config = Object.assign({}, defaultConfig, getConfig())
+
+function applyConfig () {
+  mainWindow.webContents.send('config-apply')
+}
+
+ipc.on('configUpdated', function (event, newConfig) {
+  global.config = Object.assign({}, defaultConfig, global.config, newConfig)
+  saveConfig()
+  applyConfig()
+})
+