Webpack with babel-loader not recognizing import keyword

问题

I have this webpack.config.js:

module.exports = {
  entry: './src/admin/client/index.jsx',
  output: {
    filename: './src/admin/client/static/js/app.js'
  },
  loaders: [
    {
      test: /\.jsx?$/,
      loader: 'babel',
      exclude: /node_modules/,
      query: {
        optional: ['runtime']
      }
    }
  ],
  resolve: {
    extensions: ['', '.js', '.jsx']
  }
};

...yet I still get this error:

$ webpack -v
Hash: 2a9a40224beb025cb433
Version: webpack 1.10.5
Time: 44ms
   [0] ./src/admin/client/index.jsx 0 bytes [built] [failed]

ERROR in ./src/admin/client/index.jsx
Module parse failed: /project/src/admin/client/index.jsx Line 1: Unexpected reserved word
You may need an appropriate loader to handle this file type.
| import React from 'react';
| import AdminInterface from './components/AdminInterface';

I have:

• Installed webpack globally and locally
• Installed babel-loader, babel-core, and babel-runtime
• Installed babel-loader globally, just in case

Why the hell is webpack seemingly ignoring babel-loader? Or does babel-loader not work with modules?

Update:

It looks like babel handles the input file just fine. When I run:

./node_modules/babel/bin/babel.js ./src/admin/client/index.jsx

...it outputs ES5 as expected. Therefore, it seems to me like somehow webpack isn't properly loading babel-loader.

回答1:

This looks like a case of operator error. My webpack.config.js structure was not correct. Specifically, I needed to put the loader details inside of a module section:

module.exports = {
  entry: './src/admin/client/index.jsx',
  output: {
    filename: './src/admin/client/static/js/app.js'
  },
  module: {
    loaders: [
      {
        test: /\.jsx?$/,
        loader: 'babel',
        exclude: /node_modules/,
        query: {
          optional: ['runtime']
        }
      }
    ],
    resolve: {
      extensions: ['', '.js', '.jsx']
    }
  }
};

回答2:

I fixed the same problem by including the es2015 and react presets and then adding them to the webpack.config.js file.

npm install --save-dev babel-preset-es2015 npm install --save-dev babel-preset-react

as explained in this post: https://www.twilio.com/blog/2015/08/setting-up-react-for-es6-with-webpack-and-babel-2.html

my full webpack.config.js file:

module.exports = {
  context: __dirname + "/src",
  entry: './main',
  output: {
    path: __dirname + "/build",
    filename: "bundle.js"
  },
  module: {
    loaders: [
      { 
        test: /\.js$/,
        exclude: /node_modules/,
        loader: "babel-loader",
        query: {
          presets: ['es2015', 'react']
        }
      }
    ],
    resolve: {
      extensions: ['.js', '.jsx']
    }
  }
};

回答3:

What is the version of your babel?If babel version is up to 6+.You need to identify the preset 'es2015' and 'react' like this

module: {
  loaders: [
    {
      test: /\.jsx?$/,
      exclude: /(node_modules|bower_components)/,
      loader: 'babel', // 'babel-loader' is also a legal name to reference
      query: {
        presets: ['react', 'es2015']
      }
    }
  ]
}

Don't forget to install these modules:

npm install babel-loader babel-core babel-preset-es2015 babel-preset-react --save-dev

来源：https://stackoverflow.com/questions/31799558/webpack-with-babel-loader-not-recognizing-import-keyword