[javascript] "You may need an appropriate loader to handle this file type" with Webpack and Babel

I am trying to use Webpack with Babel to compile ES6 assets, but I am getting the following error message:

You may need an appropriate loader to handle this file type.
| import React from 'react';
| /*
| import { render } from 'react-dom'

Here is what my Webpack config looks like:

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

module.exports = {
  entry: './index',
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'bundle.js',
    publicPath: '/dist/'
  },
  module: {
    loaders: [
      {
        test: /\.jsx?$/,
        loader: 'babel-loader',
        exclude: /node_modules/
      }
    ]
  }
}

Here is the middleware step that makes use of Webpack:

var webpack = require('webpack');
var webpackDevMiddleware = require('webpack-dev-middleware');
var config = require('./webpack.config');

var express = require('express');
var app = express();
var port = 3000;

var compiler = webpack(config);
app.use(webpackDevMiddleware(compiler, {
  noInfo: true,
  publicPath: config.output.publicPath
}));

app.get('/', function(req, res) {
  res.sendFile(__dirname + '/index.html');
});

app.listen(port, function(err) {
  console.log('Server started on http://localhost:%s', port);
});

All my index.js file is doing is importing react, but it seems like the 'babel-loader' is not working.

I am using 'babel-loader' 6.0.0.

This one throw me for a spin. Angular 7, Webpack I found this article so I want to give credit to the Article https://www.edc4it.com/blog/web/helloworld-angular2.html

What the solution is: //on your component file. use template as webpack will treat it as text template: require('./process.component.html')

for karma to interpret it npm install add html-loader --save-dev { test: /.html$/, use: "html-loader" },

Hope this helps somebody

Make sure you have the es2015 babel preset installed.

An example package.json devDependencies is:

"devDependencies": {
  "babel-core": "^6.0.20",
  "babel-loader": "^6.0.1",
  "babel-preset-es2015": "^6.0.15",
  "babel-preset-react": "^6.0.15",
  "babel-preset-stage-0": "^6.0.15",
  "webpack": "^1.9.6",
  "webpack-dev-middleware": "^1.2.0",
  "webpack-hot-middleware": "^2.0.0"
},

Now configure babel-loader in your webpack config:

{ test: /\.js$/, loader: 'babel-loader', exclude: /node_modules/ }

add a .babelrc file to the root of your project where the node modules are:

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

More info:

• babeljs.io - using babel with webpack

• babeljs.io - docs on .babelrc

• react-webpack-cookbook - configure react with webpack

• a react-webpack-example repo

When using Typescript:

In my case I used the newer syntax of webpack v3.11 from their documentation page I just copied the css and style loaders configuration form their website. The commented out code (newer API) causes this error, see below.

  module: {
        loaders: [{
                test: /\.ts$/,
                loaders: ['ts-loader']
            },
            {
                test: /\.css$/,
                loaders: [
                    'style-loader',
                    'css-loader'
                ]
            }
        ]
        // ,
        // rules: [{
        //     test: /\.css$/,
        //     use: [
        //         'style-loader',
        //         'css-loader'
        //     ]
        // }]
    }

The right way is to put this:

    {
        test: /\.css$/,
        loaders: [
            'style-loader',
            'css-loader'
        ]
    }

in the array of the loaders property.

Due to updates and changes overtime, version compatibility start causing issues with configuration.

Your webpack.config.js should be like this you can also configure how ever you dim fit.

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

module.exports = {
  entry: './src/js/app.js',
  devtool: 'source-map',
    mode: 'development',
  module: {
    rules: [{
      test: /\.js$/,
      exclude: /node_modules/,
      use: ["babel-loader"]
    },{
      test: /\.css$/,
      use: ['style-loader', 'css-loader']
    }]
  },
  output: {
    path: path.resolve(__dirname, './src/vendor'),
    filename: 'bundle.min.js'
  }
};

Another Thing to notice it's the change of args, you should read babel documentation https://babeljs.io/docs/en/presets

.babelrc

{
    "presets": ["@babel/preset-env", "@babel/preset-react"]
}

NB: you have to make sure you have the above @babel/preset-env & @babel/preset-react installed in your package.json dependencies

BABEL TEAM UPDATE:

We're super excited that you're trying to use ES2015 syntax, but instead of continuing yearly presets, the team recommends using babel-preset-env. By default, it has the same behavior as previous presets to compile ES2015+ to ES5

If you are using Babel version 7 you will need to run npm install @babel/preset-env and have "presets": ["@babel/preset-env"] in your .babelrc configuration.

This will compile all latest features to es5 transpiled code:

Prerequisites:

1. Webpack 4+
2. Babel 7+

Step-1:: npm install --save-dev @babel/preset-env

Step-2: In order to compile JSX code to es5 babel provides @babel/preset-react package to convert reactjsx extension file to native browser understandable code.

Step-3: npm install --save-dev @babel/preset-react

Step-4: create .babelrc file inside root path path of your project where webpack.config.js exists.

{
  "presets": ["@babel/preset-env", "@babel/preset-react"]
}

Step-5: webpack.config.js

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
    mode: 'development',
    entry: path.resolve(__dirname, 'src/index.js'),
    output: {
        path: path.resolve(__dirname, 'output'),
        filename: 'bundle.js'
    },
    resolve: {
        extensions: ['.js', '.jsx']
    },
    module: {
        rules: [{
                test: /\.(js|jsx)$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader'
                }
            },
            {
                test: /\.css$/i,
                use: ['style-loader', 'css-loader'],
            }
        ]
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: "./public/index.html",
            filename: "./index.html"
         })
    ]
}

In my case, I had such error since import path was wrong:

Wrong: import Select from "react-select/src/Select"; // it was auto-generated by IDE ;)

Correct: import Select from "react-select";

If you are using Webpack > 3 then you only need to install babel-preset-env, since this preset accounts for es2015, es2016 and es2017.

var path = require('path');
let webpack = require("webpack");

module.exports = {
    entry: {
        app: './app/App.js',
        vendor: ["react","react-dom"]
    },
    output: {
        filename: 'bundle.js',
        path: path.resolve(__dirname, '../public')
    },
    module: {
        rules: [{
            test: /\.jsx?$/,
            exclude: /node_modules/,
            use: {
                loader: 'babel-loader?cacheDirectory=true',
            }
        }]
    }
};

This picks up its configuration from my .babelrc file:

{
    "presets": [
        [
            "env",
            {
                "targets": {
                    "browsers":["last 2 versions"],
                    "node":"current"
                }
            }
        ],["react"]
    ]
}