前端无法引用后端模块jsonwebtoke
你好，我在vue组件中引入jsonwebtoken模块时，报错如下：


 ERROR  Failed to compile with 2 errors                                                                         22:10:55

These dependencies were not found:

* net in ./~/joi/lib/string.js
* dns in ./~/isemail/lib/isemail.js

To install them, you can run: npm install --save net dns
> Listening at http://localhost:8080


这个要怎么解决，按它的提示安装额外的后端模块也不奏效。。