babel-loader jsx SyntaxError:意外的令牌

Question

我是React + Webpack的初学者.

我在我的hello world web应用程序中发现了一个奇怪的错误.

我在webpack中使用babel-loader来帮助我将jsx转换为js,但看起来babel无法理解jsx语法.

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"
}

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"}
      ]
  }
};

这是我的 app/main.js

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

这是错误信息

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)

谢谢你们.

Answer 1

添加"babel-preset-react"

npm install babel-preset-react

并在webpack.config.js中为babel-loader添加"预设"选项

(或者你可以将它添加到.babelrc或package.js:http://babeljs.io/docs/usage/babelrc/ )

这是一个示例webpack.config.js:

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

最近发布了Babel 6并发生了重大变化:https: //babeljs.io/blog/2015/10/29/6.0.0

如果您使用的是react 0.14,则应使用ReactDOM.render()(from require('react-dom'))而不是React.render():https://facebook.github.io/react/blog/#changelog

更新2018年

Rule.query已被弃用,转而使用Rule.options.webpack 4中的用法如下:

npm install babel-loader babel-preset-react

然后在你的webpack配置中(作为module.exports对象中的module.rules数组中的一个条目)

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

Answer 2

从babel 5迁移到babel 6时,我遇到了类似的问题.

我只是运行babel来编译src到lib文件夹babel src --out-dir lib

我将分享我对babel 6的设置:

确保您有以下巴贝尔6个devDependencies安装

"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"

将.babelrc文件添加到项目中:

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

Answer 3

由于上面的答案仍然让一些人处于黑暗中,这就是完整的webpack.config.js可能是这样的:

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;

Answer 4

对我来说,解决方案是.babelrc使用以下内容创建文件:

{
  "presets": ["react", "es2015", "stage-1"]
}

Answer 5

以下方式帮助了我(包括反应热,babel加载器和es2015,反应预设):

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