JSX not allowed in files with extension ' .js' with eslint-config-airbnb

I've installed eslint-config-airbnb that is supposed to pre configure ESLINT for React:

> Our default export contains all of our ESLint rules, including > ECMAScript 6+ and React. It requires eslint, eslint-plugin-import, > eslint-plugin-react, and eslint-plugin-jsx-a11y.

My .eslintrc extending its configuration:

{ "extends": "eslint-config-airbnb",
  "env": {
    "browser": true,
    "node": true,
    "mocha": true
  },
  "rules": {
    "new-cap": [2, { "capIsNewExceptions": ["List", "Map", "Set"] }],
    "react/no-multi-comp": 0,
    "import/default": 0,
    "import/no-duplicates": 0,
    "import/named": 0,
    "import/namespace": 0,
    "import/no-unresolved": 0,
    "import/no-named-as-default": 2,
    "comma-dangle": 0,  // not sure why airbnb turned this on. gross!
    "indent": [2, 2, {"SwitchCase": 1}],
    "no-console": 0,
    "no-alert": 0,
    "linebreak-style": 0
  },
  "plugins": [
    "react", "import"
  ],
  "settings": {
    "import/parser": "babel-eslint",
    "import/resolve": {
      "moduleDirectory": ["node_modules", "src"]
    }
  },
  "globals": {
    "__DEVELOPMENT__": true,
    "__CLIENT__": true,
    "__SERVER__": true,
    "__DISABLE_SSR__": true,
    "__DEVTOOLS__": true,
    "socket": true,
    "webpackIsomorphicTools": true
  }
}

Unfortunatelly I'm getting the following error when linting a .js file with React JSX code inside it:

 error  JSX not allowed in files with extension '.js'              react/jsx-filename-extension

Wasn't eslint-config-airbnb configured react to support JSX already, as stated ?

What should be done to remove that error ?

Either change your file extensions to .jsx as mentioned or disable the jsx-filename-extension rule. You can add the following to your config to allow .js extensions for JSX.

"rules": {
  "react/jsx-filename-extension": [1, { "extensions": [".js", ".jsx"] }],
}

It's work for me. hope to help you.

1. disable jsx-filename-extension in .eslintrc:

   "rules": { "react/jsx-filename-extension": [0] }

2. in webpack.config.js:

   resolve: { extensions: ['.js', '.jsx'] },

Call me a dummy if it does not work for you

    "rules": {
        "react/jsx-filename-extension": [0],
        "import/extensions": "off"
    }

If you don't want to change your file extension, you can export a function that returns jsx, and then import and call that function in your js file.

// greeter.jsx

import React from 'react';

export default name => (
  <div>
    {`Hello, ${name}!`}
  </div>
);

and then

// index.js

import ReactDOM from 'react-dom';
import greeter from './components/greeter';

const main = document.getElementsByTagName('main')[0];

ReactDOM.render(greeter('World'), main);

Following React documentation:

> Each JSX element is just syntactic sugar for calling React.createElement(component, props, ...children).

Following Airbnb's style guide:

> Do not use React.createElement unless you’re initializing the app from a file that is not JSX.

You could do this:

    //index.js
    const app = React.createElement(App);
    ReactDOM.render(app, document.getElementById('root'));

To expound on Martin's answer, it seems that it is not possible, currently, to use JSX in React Native. A PR was created but reverted due to concerns about fragmentation and unknown consequences of having things like index.ios.jsx. I'm not sure how AirBnb works around this or if they do, but I have used basically the same rules block as Martin.

For future readers who want to write jsx in .js files:

0. Install npm i react react-dom even if you think you're not writing react.
1. Install npm i -D @babel/preset-react
2. In babel config: plugins: ['@babel/plugin-transform-react-jsx']
3. you should setup module.rules for /\.jsx?$/ files with babel-loader (so you will need to install npm i -D babel-loader too)