编译反应与webpack语法错误

Question

I'm a little bit new to webpack with babel loader and eslint and I'm trying to compile a very basic application and I get this weird syntax error that I can't figure out

This is my index.js, where I get the compiling error

const store = configureStore()

render(
  <Router>
    <Root store={ store } />
  </Router>,
  document.getElementById('console_root')
)

and this is the error I get:

ERROR in ./src/index.js
Module build failed: SyntaxError: Unexpected token (19:2)

  17 |
  18 | render(
> 19 |   <Router>
     |   ^
  20 |     <Root store={ store } />
  21 |   </Router>,
  22 |   document.getElementById('console_root')

npm ERR! code ELIFECYCLE
npm ERR! errno 2

and this is my webpack.config.js file

var webpack = require('webpack')
var path = require('path')

module.exports = {
  entry: {
    main: path.resolve(__dirname, 'src', 'index.js')
  },
  resolve: {
    extensions: ['*', '.js', '.jsx']
  },
  output: {
    path: path.resolve(__dirname, '..'),
    publicPath: '/',
    filename: 'bundle.js'
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: ['babel-loader', 'eslint-loader']
      },
      {
        test: /\.scss$/,
        use: ['style-loader', 'css-loader', 'sass-loader']
      }
    ]
  },
  plugins: [
    new webpack.optimize.UglifyJsPlugin({
      compress: {
        warnings: false
      }
    }),
    new webpack.DefinePlugin({
      'process.env': {
        NODE_ENV: '"production"'
      }
    })
  ]
}

and these are my dependencies:

    "dependencies": {
    "material-ui": "^1.0.0-beta.26",
    "material-ui-icons": "^1.0.0-beta.17",
    "prop-types": "^15.6.0",
    "react": "^16.2.0",
    "react-dom": "^16.2.0",
    "react-redux": "^5.0.6",
    "react-router-dom": "^4.2.2",
    "redux": "^3.7.2"
  },
  "devDependencies": {
    "babel-core": "^6.26.0",
    "babel-eslint": "^8.1.2",
    "babel-loader": "^7.1.2",
    "css-loader": "^0.28.7",
    "eslint": "^4.14.0",
    "eslint-loader": "^1.9.0",
    "eslint-plugin-react": "^7.5.1",
    "react-scripts": "^1.0.17",
    "sass-loader": "^6.0.6",
    "style-loader": "^0.19.1",
    "webpack": "^3.10.0"
  }

any ideas what am I doing wrong?

Answer 1

Seems like you missed to add react preset to your webpack.config.js file or to .babelrc .

First you should install it: npm i babel-preset-react --save-dev Then add react preset to your webpack config like the following

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

Or create a new file called .babelrc and add it there

// .babelrc
{
  "presets": ["react"]
}

It should work for you.

Answer 2

I guess you need to create a .babelrc file with content in it

{
  "presets": [
    "es2015",
    "react"
   ],
}

This will tell babel to transpile es6 to es5 and also tell there is a react project and it will handle accordingly.For these there are two packages you need which will do the job

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

Check this blog for more info