how to prevent mini-css-extract-plugin from creating a js entrypint - express

Question

I am relatively new to express + webpack, so i am unclear wether this is intended or not, and if not, how to properly configure it. the question is around the additional asset & entry point created when using the mini-css-extract-plugin.
webpack config:
Extract = require('mini-css-extract-plugin');
path = require('path');
Write = require('write-file-webpack-plugin');
module.exports = {
mode: 'development',
entry: {
demo_scripts: path.resolve('server', 'scripts', 'demo.js'),
demo_styles: path.resolve('server', 'styles', 'demo.css')
},
output: {
path: path.resolve('.tmp'),
filename: '[name].js'
},
plugins: [new Write(), new Extract()],
module: {
rules: [
{
test: /\.js$/,
use: [
{
loader: 'babel-loader',
options: {
presets: ['babel-preset-env']
}
}
]
},
{
test: /\.css/,
use: [
{
loader: Extract.loader
},
{
loader: 'css-loader'
}
]
}
]
}
};
webpack output
Asset Size Chunks Chunk Names
demo_scripts.js 3.91 KiB demo_scripts [emitted] demo_scripts
demo_styles.css 36 bytes demo_styles [emitted] demo_styles
demo_styles.js 3.89 KiB demo_styles [emitted] demo_styles
Entrypoint demo_scripts = demo_scripts.js
Entrypoint demo_styles = demo_styles.css demo_styles.js
my question is, why is demo_styles.js being created? although the css is being extracted, it almost seems like webpack is still creating a bundled js with css, but when i view that file, the only line in it is
eval("// extracted by mini-css-extract-plugin\n\n//# sourceURL=webpack:///./server/styles/demo.css?");
can anyone help explain what is going on here?
UPDATE
if i remove the demo_styles entry point, and configure it via the plugin init, no css asset is built.
({
plugins: [
new Write(),
new Extract({
filename: 'demo_styles.css'
})
]
});
Asset Size Chunks Chunk Names
demo_scripts.js 3.91 KiB demo_scripts [emitted] demo_scripts
Entrypoint demo_scripts = demo_scripts.js
the repo for this is here (note the express branch) https://github.com/brewster1134/bumper/tree/express

Answer 1

There are two workarounds for your problem. For both of them, you need to change the entry point of the Webpack configuration file. I, personally, prefer the first option.
Option 1:
Change the entry to the following:
entry: {
demo: [
path.resolve('server', 'scripts', 'demo.js'),
path.resolve('server', 'styles', 'demo.css'),
]
}
This will generate the following outputs (based on the filename you provided for Extract class and output section:
demo.js
demo_styles.css
Option 2:
For this option, you need to remove the CSS file from the entry point and import it inside the JS file:
webpack.config.js
...
entry: path.resolve('server', 'scripts', 'demo.js'),
...
demo.js
import './../styles.demo.css'
//rest of your JS codes
This solution will generate the same output as Option1

Answer 2

Webpack pulls everything into a js file, then MiniCssExtractPlugin takes it out of that file, leaving a blank js file with // extracted by mini-css-extract-plugin.
My solution is to group your css and js in the entry section of webpack.config.js
entry: {
demo: {
import: [ path.join("server", "scripts", "demo.js"), path.join("server", "styles", "demo.css") ],
filename: "demo.js", // outputs demo.js, demo.css to your output directory
},
main: {
import: [ path.join("server", "scripts", "main.js"), path.join("server", "styles", "main.css") ],
filename: "main.js", // outputs main.js, main.css to your output directory
},
}
Also, so naming works well, use this for your plugins section:
plugins: [
new MiniCssExtractPlugin({
filename: "[name].css"
}),
],
Adjust the bundles "demo" and "main", as well as paths accordingly.

Answer 3

Please remove demo_styles from your entry point this is creating demo_styles.js.
instead you can inject css file like this:
plugins: [
new MiniCssExtractPlugin({
filename: 'demo_styles.css',
}),
Let me know if the issue still persists, Happy to help