perf: refine

Author: PanJiaChen

src/main.js

@@ -24,10 +24,13 @@ import * as filters from './filters' // global filters
  * you want to use MockJs for mock api
  * you can execute: mockXHR()
  *
+ * Currently MockJs will be used in the production environment,
+ * please remove it before going online ! ! !
  */
 if (process.env.NODE_ENV === 'production') {
-  const { mockXHR } = require('../mock').default
-  mockXHR()
+  import('../mock').then(({ mockXHR }) => {
+    mockXHR()
+  })
 }
 
 Vue.use(Element, {