message: Fixed version oninstall bug
diff: @@ -122,7 +122,7 @@ message.on('FETCH_DICT_RESULT', (data, sender, sendResponse) => {
  // merge config on installed
  chrome.runtime.onInstalled.addListener(({previousVersion}) => {
  let config = defaultConfig
  - let [major, minor, patch] = previousVersion.split('.').map(n => Number(n))
  + let [major, minor, patch] = previousVersion ? previousVersion.split('.').map(n => Number(n)) : [0, 0, 0]
  if (major <= 4) {
  storage.local.clear()
  storage.sync.clear()
  