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babel-loader jsx SyntaxError: Unexpected token [duplicate]

This question already has answers here: Babel file is copied without being transformed (10 answers) Closed 5 years ago.

I'm a beginner in React + Webpack.

I found a weird error in my hello world web app.

I'm using babel-loader in webpack to help me convert jsx into js, but it seems like babel can't understand jsx syntax.

Here are my dependencies:

"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

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

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

And this is the error message

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.

That comma after the <h1> looks a little peculiar...
For newer versions of react , use the new babel modules : stackoverflow.com/a/53927457/6665568 . It has better error messages and supports new features of react.

L
Liran H

Add "babel-preset-react"

npm install babel-preset-react

and add "presets" option to babel-loader in your webpack.config.js

(or you can add it to your .babelrc or package.js: http://babeljs.io/docs/usage/babelrc/)

Here is an example webpack.config.js:

{ 
    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

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

UPDATE 2018

Rule.query has already been deprecated in favour of Rule.options. Usage in webpack 4 is as follows:

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)

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

Another question, if i want to use ES6 Syntax in future, should I install babel-preset-es2015 and do some options in config file in the same way?
You got it. presets:['es2015','react']
I'm trying to follow this but I still get the error. Could you post a complete package.json, and webpack.config.js, main.js "hello world"?
I don't know why, but seemingly the order matters in: presets:['es2015','react'] I was trying it with presets:['react','es2015'] and it failed
s
svnm

I ran into a similar issue when migrating from babel 5 to babel 6.

I was just running babel to compile the src to lib folder babel src --out-dir lib

I will share my setup for babel 6:

Ensure you have the following babel 6 devDependencies installed

"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:

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

The need for es2015 when using stage-0 was a great catch.
Was getting an error for unknown syntax at export App from './App' - realized I needed stage-0, thanks for this.
I have an example setup for react, babel and webpack here it also includes enzyme for testing css modules and universal rendering.
this worked for me without stage-0
It works for me. I did not have stage-0 in devDependencies.
C
Community

Since the answer above still leaves some people in the dark, here's what a complete webpack.config.js might look like:

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;


a
albanx

For me the solution was to create the file .babelrc with this content:

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

u
ubuntugod

The following way has helped me (includes react-hot, babel loaders and es2015, react presets):

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

This helped me when I was following the Django plus React stuff in this link: owaislone.org/blog/webpack-plus-reactjs-and-django This is (I presume) an alternative to using a .babelrc file as mentioned above.
this also helped me even though my error is not the same as the original question.
I had to delete '?presets[]=es2015&presets[]=react'. Adding 'state-0' into .babelrc helped to fix problem.
A
Aftab Naveed

For those who still might be facing issue adding jsx to test fixed it for me

test: /\.jsx?$/,

literally for days I've been trying to resolve this with every conceivable change to gulpfile.js, ...and it was this simple
j
jose920405

This works perfect for me

{
    test: /\.(js|jsx)$/,
    loader: 'babel-loader',
    exclude: /node_modules/,
    query: {
        presets: ['es2015','react']
    }
},

M
Maxime Brehin

You can find a really good boilerplate made by Henrik Joreteg (ampersandjs) here: https://github.com/HenrikJoreteg/hjs-webpack

Then in your 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
})

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