react-router引入Router时报错

1. 文件布局

routes/index.js

import React from 'react';
import { Router, Route, hashHistory } from 'react-router';
import Home from '../views/Home';
import Detail from '../views/Detail';

const routes = (
  <Router history={hashHistory}>
    <Route path="/" component={Home}/>
    <Route path="/detail/:id" component={Detail}/>
  Router>
);

export default routes;

app.js

import ReactDOM from 'react-dom';
import routes from './routes';

ReactDOM.render(routes, document.getElementById('root'));

webpack.config.js

const path = require('path');

module.exports = {
  entry: './src/app.js',
  output: {
    path: path.resolve(__dirname, 'build'),
    filename: 'app.bundle.js',
    publicPath: '/build',
  },
  module: {
    rules: [{
      test: /\.js$/,
      loader: 'babel-loader',
      exclude: /node_modules/,
    }]
  }
}

package.json

{
  "scripts": {
    "build": "webpack"
  },
  "dependencies": {
    "babel-core": "^6.26.0",
    "babel-loader": "^7.1.2",
    "react": "^15.6.1",
    "react-dom": "^15.6.1",
    "react-redux": "^5.0.2",
    "react-router": "^3.0.2",
    "redux": "^3.6.0",
    "redux-logger": "^2.8.1",
    "redux-thunk": "^2.2.0",
    "react-router-redux": "^4.0.8",
    "whatwg-fetch": "^2.0.3"
  },
  "devDependencies": {
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "webpack": "^3.10.0"
  }
}

2. 错误展示

当运行npm run build时报出如下错误

3.错误分析

• 刚开始是因为react-route加载的是V4版本的，报这样的错很正常，但当安装V3版本时依旧报这样的错，查了很久才知道是因为：routes/index.js写的是es2015的语法，但却没有加ES2015的babel preset，也没有加react的preset。

4.解决方案

在webpack.config.js中的

module: {
    rules: [{
      test: /\.js$/,
      loader: 'babel-loader',
      exclude: /node_modules/,
    }]
  }

修改为

module: {
    rules: [{
      test: /\.js$/,
      loader: ['babel-loader?presets[]=react&presets[]=es2015'],
      exclude: /node_modules/,
    }]
  }

然后运用npm install --save-dev babel-preset-react babel-preset-es2015再安装一下preset就可以解决了，再次运行npm run build时正常显示为

> @ build E:\self\redux-blog
> webpack

Hash: e4c4a9ef55a286df216f
Version: webpack 3.10.0
Time: 2034ms
        Asset    Size  Chunks                    Chunk Names
app.bundle.js  908 kB       0  [emitted]  [big]  main
 [115] ./src/app.js 416 bytes {0} [built]
 [215] ./src/routes/index.js 866 bytes {0} [built]
 [243] ./src/views/Home.js 3.24 kB {0} [built]
 [244] ./src/views/Detail.js 3.26 kB {0} [built]
    + 241 hidden modules