Develop Reference

Why can't Webpack resolve ‘babel-loader’?

When I configure Webpack for this code base, Webpack complains that it Can't resolve 'babel-loader'. What exactly is failing, and how can I ask Webpack what its complaint is?
The Webpack configuration:
// webpack.config.js
const path = require('path');
const webpack = require('webpack');
module.exports = {
entry: './source/main.jsx',
output: {
path: path.resolve(__dirname, 'dist'),
filename: 'app.js',
},
resolve: {
modules: [
path.resolve(__dirname, 'source'),
'/usr/share/javascript',
'/usr/lib/nodejs',
],
},
module: {
loaders: [
// Transform JSX with React.
{
test: /\.jsx$/,
loader: 'babel-loader',
query: {
presets: ['es2015', 'react'],
},
},
],
},
};
The entry module:
// source/main.jsx
"use strict";
import Application from './components/Application';
const applicationElement = <Application />;
ReactDOM.render(
applicationElement,
document.getElementById('application'),
);
Is the problem something like a search path, and if so why can't the error tell me what setting I need to correct?
The babel-loader module is definitely installed. (I therefore don't want to install it again – so npm install won't help – I am trying to tell Webpack to use it from the already-installed location.) Its package definition is at /usr/lib/nodejs/babel-loader/package.json.
I've pointed Webpack's resolver there – instead of its default resolver behaviour – using the resolve.modules list of search paths. Correct?
So the resolver should be able to find it there by the specified search path /usr/lib/nodejs and the name babel-loader, no?
(This raises a separate question, about how to convince Webpack to just tell me what it's looking for so it can be diagnosed more easily.)
How can I tell Webpack the specific location it should use to resolve that babel-loader name?

The Webpack configuration setting resolve is for modules that are imported. The loaders are resolved differently; the resolveLoader setting configures how to resolve the loaders specifically.
So, adding resolveLoader to the Webpack configuration works:
// webpack.config.js
const path = require('path');
const webpack = require('webpack');
module.exports = {
entry: './source/main.jsx',
output: {
path: path.resolve(__dirname, 'dist'),
filename: 'app.js',
},
resolve: {
// Configure how Webpack finds modules imported with `import`.
modules: [
path.resolve(__dirname, 'source'),
'/usr/share/javascript',
'/usr/lib/nodejs',
],
},
resolveLoader: {
// Configure how Webpack finds `loader` modules.
modules: [
'/usr/lib/nodejs',
],
},
module: {
loaders: [
// Transform JSX with React.
{
test: /\.jsx$/,
loader: 'babel-loader',
query: {
presets: ['es2015', 'react'],
},
},
],
},
};

I think that the webpack.config you're looking for is the following:
module: {
loaders: [
{test: /\.js$/, include: path.join(__dirname, 'src'), loaders: ['babel']},
]
}
Hope helps :)

webpack error -ERROR in bundle.js from UglifyJs Unexpected token: name (urlParts)

I am starting to learn webpack. I created a simple config file:
const path = require('path');
const webpack = require('webpack');
module.exports = {
context: __dirname,
entry: './src/index.js',
output: {
filename: 'bundle.js',
publicPath: '/',
path: path.resolve(__dirname, 'dist')
},
devtool: 'inline-source-map',
devServer: {
contentBase: path.join(__dirname, 'dist'),
hot: true
},
plugins: [new webpack.HotModuleReplacementPlugin()],
module: {
rules: [
{
test: /\.js$/,
exclude: /node_modules/,
include: path.join(__dirname, 'src'),
use: ['babel-loader']
},
{
test: /\.css$/,
use: ['style-loader', 'css-loader']
},
{
test: /\.(png|svg|jpg|gif)$/,
use: ['file-loader']
},
{
test: /\.(woff|woff2|eot|ttf|otf)$/,
use: ['file-loader']
}
]
}
};
Then I created src/index.js with a simple console.log('hello').
In package.json I put this:
"start": "webpack-dev-server --config webpack.config.local.js -p",
When I run "npm start" in the terminal I get this weird error:
ERROR in bundle.js from UglifyJs
Unexpected token: name (urlParts) [(webpack)-dev-server/client?http:/localhost:8080:24,0][bundle.js:4026,4]
The bundle.js looks very weird since I haven't write all this code. I googled but cannot find the solution, do you have any idea what I am doing wrong? Thanks!
Edit: I added this in .babelrc but still same error:
{"presets": ["react", "stage-2", "es2015"]}

Remove the -p from your npm script, this is why is minifying the code.
It seems that you are using webpack-dev-server and a config.local file so I assume this is only for local development, in this case the -p from webpack it's not needed.
Regarding the size of bundle.js I see you are excluding the node_modules folder, so it seems ok for me. Try to add a new script in your package.json like this:
"build": ""webpack --config webpack.config.local.js"
and see the file that will be created, so you can better understand what is going on.
Hope this help, cheers!

How to setup react properly

I have been following the react setup instructions on codecademy:
When I type in "npm run build" into the terminal I get this error:
I can't seem to figure out how to get it to work.
Here is the link to my code on my github:
https://github.com/throwkill999/react_demo

The error tells you that output.build is not a valid option. You probably meant to use output.path. There are other problems with how you concatenate __dirname in some places, because you need a leading / for them. But it's better to use path.resolve for that.
Your config would look like this:
var path = require('path');
var HTMLWebpackPlugin = require('html-webpack-plugin');
var HTMLWebpackPluginConfig = new HTMLWebpackPlugin({
template: path.resolve(__dirname, 'app/index.html'),
filename: 'index.html',
inject: 'body'
});
module.exports = {
entry: path.resolve(__dirname, 'app/index.js'),
module: {
loaders: [
{
test: /\.js$/,
exclude: /node_modules/,
loader: 'babel-loader'
}
]
},
output: {
filename: 'transformed.js',
path: path.resolve(__dirname, 'build')
},
plugins: [HTMLWebpackPluginConfig]
};
Also in ./app/index.js you have a typo, it should be ./components/Apps (you forgot the s).

webpack-dev-server watches and compiles files correctly, but browser can't access them

EDIT: Link to github repo where this example is hosted is here in case someone wants to run it
I'm getting the near exact same problem as another user (you can find the question here), in that running the webpack-dev-server does actually compile and watch files correctly (seeing the console output in the terminal), but the browser still can't view my site correctly. This is my webpack.config.js file:
var webpack = require('webpack'),
path = require('path'),
// webpack plugins
CopyWebpackPlugin = require('copy-webpack-plugin');
var config = {
context: path.join(__dirname,'app'),
entry: './index.js',
output: {
path: path.join(__dirname, 'public'),
filename: 'bundle.js',
publicPath: path.join(__dirname, 'public')
},
devServer: {
// contentBase: './public/'
},
plugins: [
// copies html to public directory
new CopyWebpackPlugin([
{ from: path.join(__dirname, 'app', 'index.html'),
to: path.join(__dirname, 'public')}
]),
// required bugfix for current webpack version
new webpack.OldWatchingPlugin()
],
module: {
loaders: [
// uses babel-loader which allows usage of ECMAScript 6 (requires installing babel-preset-es2015)
{test: /\.js$/, loader: 'babel', exclude: /node_modules/, query: { presets: ['es2015']}},
// uses the css-loader (loads css content) and style-loader (inserts css from css-loader into html)
{test: /\.css$/, loader: 'style!css', exclude: /node_modules/}
]
}
};
module.exports = config;
And this is my directory structure:
+--- webpack/
+--- app/
+--- index.html
+--- index.js
+--- styles.css
+--- package.json
+--- webpack.config.js
Currently, running webpack-dev-server outputs the following in the browser (note the lack of the public/ directory which is where webpack normally outputs my html and javascript bundle):
EDIT: Adding the devServer.contentBase property and setting it to public gets the browser to return a 403 error not found as shown here:

Okay, so I was able to reproduce the issue that you have on my project. To fix the issue I changed some things.
Here is what I have set up. I'm defining a bit less in the output and using jsx instead of js, but the results should be the same. You can replace my src with wherever your source code is.
const config = {
entry: './src/App.jsx',
output: {
filename: 'app.js'
},
module: {
loaders: [
{
test: /\.jsx?$/,
loader: 'babel-loader',
exclude: /node_modules/,
query: {
presets: ['es2015', 'react', 'stage-0'],
plugins: ['add-module-exports']
}
},
{
include: /\.json$/, loaders: ['json-loader']
},
{
test: /\.scss$/,
loaders: ['style', 'css?modules', 'sass']
},
{
test: /\.(eot|svg|ttf|woff|woff2)$/,
loader: 'file?name=fonts/[name].[ext]'
}
]
},
plugins: [
new webpack.ProvidePlugin({
'Promise': 'exports?module.exports.Promise!es6-promise',
'fetch': 'imports?self=>global!exports?global.fetch!isomorphic-fetch'
}),
new webpack.IgnorePlugin(/^\.\/locale$/, [/moment$/]),
new webpack.optimize.OccurenceOrderPlugin(),
new webpack.optimize.DedupePlugin(),
new webpack.DefinePlugin({
'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV)
})
],
resolve: {
root: path.resolve('./src')
},
devServer: {
contentBase: 'src'
}
};
So basically you would want this output in terminal:
webpack result is served from / - tells us that whatever we build from will be at the root
content is served from src - tells us that it's building from that directory
Hope this helps

Webpack error when importing CSS vendor library into index.js

I am moving existing javascript vendor libraries into a webpack setup, where possible using npm to install an npm module and deleting the old script tag on the individual page as bundle.js and bundle.css include it
In index.js, I have the following
import 'materialize-css/dist/css/materialize.min.css';
However, when webpack is run, it errors with the following
Module parse failed: .......Unexpected character ''
You may need an appropriate loader to handle this file type.
So, for some reason, webpack is looking at the entire materialize folder, rather than just the single minified css file, and is then error when it comes across materialize/fonts directory.
I am unclear why this is happening, and what to do to stop it. Any advice would be greatly appreciated.
My webpack config is below
const webpack = require('webpack');
const path = require('path');
var precss = require('precss');
var autoprefixer = require('autoprefixer');
var ExtractTextPlugin = require("extract-text-webpack-plugin");
var postcssImport = require('postcss-import');
module.exports = {
context: __dirname + '/frontend',
devtool: 'source-map',
entry: "./index.js",
output: {
filename: 'bundle.js',
path: path.join(__dirname, './static')
},
module: {
loaders: [
{
test: /\.js$/,
loader: 'babel',
exclude: /node_modules/,
query: {
presets: ['es2015']
}
},
{
test: /\.css$/,
loader: ExtractTextPlugin.extract('style-loader', '!css-loader?sourceMap&importLoaders=1!postcss-loader')
}
]
},
plugins: [
new ExtractTextPlugin("si-styles.css")
],
postcss: function(webpack) {
return [
postcssImport({ addDependencyTo: webpack }), // Must be first item in list
precss,
autoprefixer({ browsers: ['last 2 versions'] })
];
},
}