ionic Error: Cannot find module "."

使用VScode开发ionic移动应用时，碰到如下错误：

Uncaught Error: Cannot find module "."
        at webpackMissingModule (index.js:3)
        at e.code (index.js:3)
        at Object. (index.js:9)
        at __webpack_require__ (bootstrap 62d6a5897825ac327001:54)
        at Object.690 (slide.transition.ts:67)
        at __webpack_require__ (bootstrap 62d6a5897825ac327001:54)
        at Object.495 (main.js:1885)
        at __webpack_require__ (bootstrap 62d6a5897825ac327001:54)
        at Object.487 (notification-api.ts:6)
        at __webpack_require__ (bootstrap 62d6a5897825ac327001:54)




原因很怪异，只要在constructor中使用

NavController、ModalController等

就报错，经网上查询，终于看到了答案，原因就是在写NavController时，IDE提示从“ionic-angular/umd”导入，就直接用了，正是这个“umd”造成的错误，把从“ionic-angular/umd”导入

import { NavController } from 'ionic-angular/umd';

改为从“ionic-angular"导入

import { NavController } from 'ionic-angular';

就Ok了

具体原因不明，有了解的朋友请赐教！