本文翻译自：babel-loader jsx SyntaxError: Unexpected token [duplicate]

I'm a beginner in React + Webpack. 我是React + Webpack的初学者。

I found a weird error in my hello world web app. 我在Hello World Web应用程序中发现了一个奇怪的错误。

I'm using babel-loader in webpack to help me convert jsx into js, but it seems like babel can't understand jsx syntax. 我在webpack中使用babel-loader来帮助我将jsx转换为js，但是babel似乎无法理解jsx语法。

Here are my dependencies: 这是我的依赖项：

"devDependencies": {
  "babel-core": "^6.0.14",
  "babel-loader": "^6.0.0",
  "webpack": "^1.12.2",
  "webpack-dev-server": "^1.12.1"
},
"dependencies": {
  "react": "^0.14.1"
}

Here is my webpack.config.js 这是我的webpack.config.js

var path = require('path');
module.exports = {
  entry: ['webpack/hot/dev-server',path.resolve(__dirname, 'app/main.js')],
  output: {
    path: path.resolve(__dirname, 'build'),
    filename: 'bundle.js'
  },
  module: {
      loaders: [
          { test: /\.js$/, exclude: /node_modules/, loader: "babel-loader"}
      ]
  }
};

Here is my app/main.js 这是我的app/main.js

var React = require("react");
React.render(<h1>hello world</h1>,document.getElementById("app"));

And this is the error message 这是错误消息

ERROR in ./app/main.js
Module build failed: SyntaxError: ~/**/app/main.js: Unexpected token (2:13)
  1 | var React = require("react");
> 2 | React.render(<h1>hello world</h1>,document.getElementById("app"));
    |              ^
at Parser.pp.raise (~/**/node_modules/babylon/lib/parser/location.js:24:13)

Thanks for you guys. 谢谢你们

#1楼

参考：https://stackoom.com/question/2GOaC/babel-loader-jsx-SyntaxError-意外令牌-重复

#2楼

Add "babel-preset-react" 添加“ babel-preset-react”

npm install babel-preset-react

and add "presets" option to babel-loader in your webpack.config.js 并在webpack.config.js中向babel-loader添加“预设”选项

(or you can add it to your .babelrc or package.js: http://babeljs.io/docs/usage/babelrc/ ) （或者您可以将其添加到您的.babelrc或package.js： http ://babeljs.io/docs/usage/babelrc/）

Here is an example webpack.config.js: 这是一个webpack.config.js示例：

{ 
    test: /\.jsx?$/,         // Match both .js and .jsx files
    exclude: /node_modules/, 
    loader: "babel", 
    query:
      {
        presets:['react']
      }
}

Recently Babel 6 was released and there was a major change: https://babeljs.io/blog/2015/10/29/6.0.0 最近发布了Babel 6，并进行了重大更改： https : //babeljs.io/blog/2015/10/29/6.0.0

If you are using react 0.14, you should use ReactDOM.render() (from require('react-dom') ) instead of React.render() : https://facebook.github.io/react/blog/#changelog 如果您使用ReactDOM.render() 0.14，则应该使用ReactDOM.render() （来自require('react-dom') ）而不是React.render() ： https : React.render()

UPDATE 2018 更新2018

Rule.query has already been deprecated in favour of Rule.options. 不推荐使用Rule.query，而使用Rule.options。 Usage in webpack 4 is as follows: webpack 4中的用法如下：

npm install babel-loader babel-preset-react

Then in your webpack configuration (as an entry in the module.rules array in the module.exports object) 然后在您的webpack配置中（作为module.exports对象中module.rules数组中的条目）

{
    test: /\.jsx?$/,
    exclude: /node_modules/,
    use: [
      {
        loader: 'babel-loader',
        options: {
          presets: ['react']
        }
      }
    ],
  }

#3楼

Since the answer above still leaves some people in the dark, here's what a complete webpack.config.js might look like: 由于上面的答案仍然使某些人望而却步，因此完整的webpack.config.js可能如下所示：

 var path = require('path'); var config = { entry: path.resolve(__dirname, 'app/main.js'), output: { path: path.resolve(__dirname, 'build'), filename: 'bundle.js' }, module: { loaders: [{ test: /\\.jsx?$/, loader: 'babel', query: { presets:['es2015', 'react'] } }] }, }; module.exports = config; 

#4楼

I ran into a similar issue when migrating from babel 5 to babel 6. 从babel 5迁移到babel 6时，我遇到了类似的问题。

I was just running babel to compile the src to lib folder babel src --out-dir lib 我只是在运行babel将src编译为lib文件夹babel src --out-dir lib

I will share my setup for babel 6: 我将分享Babel 6的设置：

Ensure you have the following babel 6 devDependencies installed 确保您已安装以下babel 6 devDependencies

"babel-core": "^6.7.6",
"babel-loader": "^6.2.4",
"babel-preset-es2015": "^6.6.0",
"babel-preset-react": "^6.5.0",
"babel-preset-stage-0": "^6.5.0"

Add your .babelrc file to the project: 将.babelrc文件添加到项目中：

{
  "presets": ["es2015", "stage-0", "react"]
}

#5楼

The following way has helped me (includes react-hot, babel loaders and es2015, react presets): 以下方法对我有所帮助（包括react-hot，babel装载程序和es2015，react预设）：

loaders: [
      {
        test: /\.jsx?$/,
        exclude: /node_modules/,
        loaders: ['react-hot', 'babel?presets[]=es2015&presets[]=react']
      }
]

#6楼

You can find a really good boilerplate made by Henrik Joreteg (ampersandjs) here: https://github.com/HenrikJoreteg/hjs-webpack 您可以在这里找到由Henrik Joreteg（＆sandjs）制作的非常好的样板： https ： //github.com/HenrikJoreteg/hjs-webpack

Then in your webpack.config.js 然后在您的webpack.config.js

var getConfig = require('hjs-webpack')

module.exports = getConfig({
  in: 'src/index.js',
  out: 'public',
  clearBeforeBuild: true,
  https: process.argv.indexOf('--https') !== -1
})