如果输入$npm start就会出现：所在位置 行:1 字符: 6
+ $npm start
+      ~~~~~
表达式或语句中包含意外的标记“start”。
    + CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : UnexpectedToken

如果输入npm start，就会出现

> angular2-demo@1.0.0 start C:\Users\B\Desktop\angular2-demo-master
> webpack-dev-server --inline --colors --progress --port 3000

'webpack-dev-server' 不是内部或外部命令，也不是可运行的程序
或批处理文件。

npm ERR! Windows_NT 10.0.14393
npm ERR! argv "C:\\Program Files\\nodejs\\node.exe" "C:\\Users\\B\\AppData\\Roaming\\npm\\nod
e_modules\\npm\\bin\\npm-cli.js" "start"
npm ERR! node v7.6.0
npm ERR! npm  v4.3.0
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! angular2-demo@1.0.0 start: `webpack-dev-server --inline --colors --progress --port 3
000`
npm ERR! Exit status 1

npm ERR! Failed at the angular2-demo@1.0.0 start script 'webpack-dev-server --inline --colors --progress --port 3000'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the angular2-demo package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     webpack-dev-server --inline --colors --progress --port 3000
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs angular2-demo
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!     npm owner ls angular2-demo
npm ERR! There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?

npm ERR! Please include the following file with any support request:
npm ERR!     C:\Users\B\AppData\Roaming\npm-cache\_logs\2017-03-13T06_36_58_626Z-debug.log