[Doc] optimize document site (#1013)

build/bin/build-entry.js

@@ -28,6 +28,7 @@ const install = Vue => {
   });
 };
 
+/* istanbul ignore if */
 if (typeof window !== 'undefined' && window.Vue) {
   install(window.Vue);
 }
@@ -55,26 +56,7 @@ function buildDemoEntry() {
     .map(name => `'${name}': asyncWrapper(r => require.ensure([], () => r(componentWrapper(require('./views/${name}'), '${name}')), '${name}'))`);
 
   const content = `${tips}
-import './common';
-
-import progress from 'nprogress';
-
-function asyncWrapper(component) {
-  return function(r) {
-    progress.start();
-    component(r).then(() => {
-      progress.done();
-    }).catch(() => {
-      progress.done();
-    });
-  };
-}
-
-function componentWrapper(component, name) {
-  component = component.default;
-  component.name = 'demo-' + name;
-  return component;
-}
+import { asyncWrapper, componentWrapper } from './common';
 
 export default {
   ${demos.join(',\n  ')}