webpack错误 - 您可能需要一个合适的加载器

Question

当我跑npm run watch时出现以下错误。任何人都可以告诉我原因。

ERROR in ./~/praxis/src/index.js
Module parse failed: /home/iswan/os-projects/praxis-samples/03-forms/node_modules/praxis/src/index.js Line 1: Unexpected token
You may need an appropriate loader to handle this file type.
| export { default as React } from 'react';
| export * from 'react-router';
| 
 @ ./src/main.js 5:14-31

显示错误的文件

export { default as Dispatcher } from './app/Dispatcher';
export { default as Session } from './app/Session';

export { default as MenuBar } from './ui/MenuBar';
export { default as Input } from './ui/Input';

export { default as ArrayStore } from './storage/ArrayStore';
export { default as RESTApi } from './net/RESTApi';