Importing css file to specific component react app - css

I am trying to import css to my specific component of react app.
webpack config:
{
test: /\.css$/,
loader: ExtractTextPlugin.extract({
use: 'css-loader',
}),
}
but css is not applied.
I also included the main css inside index.html. Is it the reason why I cannot apply another css file?
<link rel="stylesheet" href="../style/style.css">
Can you suggest me what's missing?

It depends on the webpack version you're using. For example, if you're using Webpack 4, then your development config would be:
{
test: /\.s?css$/, // test for scss or css files
use: [
'style-loader', // try to use style-loader or...
{
loader: 'css-loader', // try to use css-loader
options: {
sourceMap: true, // allow source maps (allows css debugging)
modules: true, // allow css module imports
camelCase: true, // allow camel case imports
localIdentName: '[local]___[hash:base64:5]', // set imported classNames with a original className and a hashed string in the DOM, for example: "exampleClassName__2fMQK"
},
},
],
}
example.css (must use camel case instead of snake case)
.exampleClassName {
text-align: center;
}
example.js
import React from 'react';
import { exampleClassName } from './example.css';
export default () => (
<h1 className={exampleClassName}>I am centered!</h1>
)
For production, you'll want to use OptimizeCSSAssetsPlugin and MiniCssExtractPlugin :
minimizer: [
new OptimizeCSSAssetsPlugin({
cssProcessorOptions: {
map: {
inline: false,
annotation: true
}
}
}),
],
{
plugins: [
new MiniCssExtractPlugin({
filename: `css/[name].[contenthash:8].css`,
chunkFilename: `[id].[contenthash:8].css`,
}),
]
}
When you run webpack to build your application for production, it'll compile the css and (when the webpack config is set up properly) will generate an index.html that automatically adds a link to the compiled stylesheet.
Webpack is a steep learning curve and there's a lot of missing options from the above examples, so if you're just trying to get it up and running, then I have a Webpack-React-Boilerplate that has (s)css modules imports and a lot more already configured for you. I've included notes within the webpack config files to help assist as to what each option is doing.
Otherwise, if you're trying to learn older versions of webpack, then you can eject the create-react-app and reverse engineer/look at their extensive webpack notes.

Related

Transpiling CSS class names in a react component is not working properly

I have a react app where I have the following component:
component.js
import styles from './styles.css';
const SomeComponent = (props) => {
return <div className={`${styles["container"]}`}>Hey :D</div>
}
export default SomeComponent;
styles.css
#value container: #f5f5f5;
.container {
background-color: red;
}
The styles["container"] should return the transpiled name of the CSS class container. Right now is returning an empty object.
All of this was working perfectly fine until I updated some dependencies for my project. In our company we had really old dependencies, so we decided to update them.
Old configuration (with this it worked)
Webpack config
Package.json
Running on node 11.0.0.
New configuration (with this everything works except what I described earlier)
Webpack config
New package.json
Running on node 14.17.3.
More info
I know that this is not a reproducible example, but I have not been able to create one. I cannot even install the dependencies alone to isolate the problem.
I have made some digging and I think the problem has to be in this part of the webpack configuration. Or maybe is having the same name for a variable and for a class. I have just realised that it works perfectly for class names with different names than values.
test: /\.css$/,
exclude: [
path.resolve(__dirname, 'node_modules/#material'),
path.resolve(__dirname, 'node_modules/#rmwc'),
path.resolve(__dirname, 'node_modules/react-dual-listbox/lib/react-dual-listbox.css'),
path.resolve(__dirname, 'node_modules/react-image-lightbox/style.css'),
path.resolve(__dirname, 'web/js/src/modules/Common/styles/material.css'),
],
use: [
{ loader: 'style-loader' },
{
loader: 'css-loader',
options: {
importLoaders: 1,
modules: { localIdentName: '[path]___[name]__[local]___[hash:base64:5]' },
},
}],
},
In the documentaion of the css loader module I found the option namedExport: true, but I cannot use it becuase that appears in the version 6.2.9 and I'm using 3.6.0 (previously I was using 2.1.1).
Any idea how to fix this?

webpack: understanding source maps when working with CSS

Introduction
I have already setup bundling for my Javascript files with webpack in my project. Now I am in the process of adding CSS files to the webpack configuration. So far, I have been including the CSS files manually in the HTML header by adding <link> elements for every CSS file I depend on (e.g. bootstrap, my own css, etc.). Obviously this is not very elegant and using webpack would be much better, so I would like to replace the link elements and bundle them via webpack.
This should be easy, everything is pretty much documented in the webpack documentation. After reading the documentation and experimenting a bit with webpack I have arrived at the configuration below which already works.
Problem
The problem with my current setup is that I would like to have proper source map support and that does not seem to work. By proper, I mean that I expect that when I run a development build with webpack and I inspect some element in Chrome DevTools, that I will see from which file and which line in the file a certain CSS class originated and that I can click on the CSS rules and the browser jumps to that file.
I do not want to have inline styles in the head element, because then the browser will show something like .foobar { <style>..</style>, rather then .foobar { app.css:154.
With my current setup I have all CSS files combined (but not minified) into one app.css file. This means that if I inspect a bootstrap class such as .btn then it appears as .btn { app.css:3003. However, what I want to achieve is that the browser shows it as .btn { bootstrap.css:3003.
So now I am trying to understand how webpack and the different plugins such as css-loader and min-css-extract-plugin apply CSS source maps, and how I can configure them to achieve a proper debugging experience.
I am not sure how relevant this is, but when I navigate in DevTools under Sources to webpack://./bootstrap/dist/css/bootstrap.css I see that it only contains a single line:
// extracted by mini-css-extract-plugin.
Webpack Setup
index.js:
window.jQuery = require('jquery/dist/jquery');
require('bootstrap/dist/css/bootstrap.css');
require('bootstrap/dist/js/bootstrap');
/* other dependencies */
webpack.config.js:
const devMode = process.env.NODE_ENV !== 'production';
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
module: {
rules: [
{ /* Javascript rules excluded */ },
{
test: /\.css$/,
use: [
{
loader: MiniCssExtractPlugin.loader
},
{
loader: 'css-loader',
options: {
sourceMap: true
}
}
]
},
{
test: /\.(png|svg|jpg|gif)$/,
use: [
'file-loader'
]
},
{
test: /\.(woff|woff2|eot|ttf|otf)$/,
use: [
'file-loader'
]
}
plugins: [
new UglifyJSPlugin (),
new HtmlWebpackPlugin({
template: 'app/index.tpl.html'
}),
new MiniCssExtractPlugin({ filename: devMode ?
'[name].css' :
'[name].[hash].css'
})
],
Conclusion
It seems I just passed the rubber duck test. While I was writing this I arrived at a solution. I will still publish the question, maybe it can help others.
The problem was that I was also using the mini-css-extract-plugin for development and not just for production. I thought that I needed to do that, because when at first I was using the style-loaded I would get styles included in the header and the browser would show me all styles as .foobar { <style>..</style>.
However, the actual problem seemed to be, that I was not using devtools. So the solution was to add devtool: devMode ? 'cheap-module-eval-source-map' : 'source-map', to the webpack configuration to conditionally use the style-loader plugin during development builds and mini-css-extract-plugin during production builds.
webpack.config.js
{
test: /\.css$/,
use: [
{
- loader: MiniCssExtractPlugin.loader,
+ loader: devMode ? 'style-loader' : MiniCssExtractPlugin.loader,
},
{
loader: 'css-loader',
options: {
sourceMap: true
}
}
]
},
/* ... */
+ devtool: devMode ? 'cheap-module-eval-source-map' : 'source-map',

How to remove unused CSS using webpack 4?

I am having problem removing unused CSS in webpack 4. It seems that most of the CSS purification plugins are dependent on extract text plugin which is not updated for version 4.
Here's my commands:
node_modules/.bin/webpack --mode=development --env.operation=separateCSS
OR
node_modules/.bin/webpack --mode=development --env.operation=bundleCSS
Here's part of my webpack.config.js:
rules: [
// Loader for SASS files
{
test: /\.s[ac]ss$/,
use: [
// Use IIFE to choose how to emit the CSS: 1. Extract as separate file 2: Bundle with the JS file
(() => {
return env.operation == "separateCSS" ? MiniCssExtractPlugin.loader : 'style-loader';
})(),
{
loader: 'css-loader',
options: {
importLoaders: 1,
url: true
}
},
{
loader: 'postcss-loader',
options: {
ident: 'postcss',
plugins: [
// Write future-proof CSS and forget old preprocessor specific syntax.
// Use the latest CSS syntax today with cssnext.
// It transforms CSS specs into more compatible CSS so you don’t need to wait for browser support.
// It parses CSS and add vendor prefixes to CSS rules using values from Can I Use.
// https://github.com/MoOx/postcss-cssnext
require('postcss-cssnext')()
]
}
},
'sass-loader'
]
}
],
plugins: [
new MiniCssExtractPlugin({
filename: "../css/[name].css"
})
]
Does anybody know how can I modify my config file so webpack can remove unused CSS?
Have you considered using something called uncss. There's a webpack plugin for it. It will look through all your CSS and compare it to your HTML, and remove anything that you're not using.
Take a look: WebPack UnCSS

Vue.js + Webpack multiple style tas output

I have several vue.js components, written in single page component format.
For each .vue file, I have less written specific for that page.
After bundling, I have several style tags, which populate the global style space. Thus, some of my classes are overlapping on different pages.
Is this the intended functionality with vue.js and webpack?
This is the default behaviour for vue-loader (which is the main plugin in the vue-webpack template).
However, if you want to you can extract all CSS into one file:
npm install extract-text-webpack-plugin --save-dev
// webpack.config.js
var ExtractTextPlugin = require("extract-text-webpack-plugin")
module.exports = {
// other options...
module: {
loaders: [
{
test: /\.vue$/,
loader: 'vue'
},
]
},
vue: {
loaders: {
css: ExtractTextPlugin.extract("css"),
// you can also include <style lang="less"> or other langauges
less: ExtractTextPlugin.extract("css!less")
}
},
plugins: [
new ExtractTextPlugin("style.css")
]
}
Check out the docs of vue-loader regarding extraction.

Adding less support to a production webpack configuration (from Facebook's create-react-app)

I have forked (or ejected) off Facebook's create-react-app project, with the requirement to add a few additional tools (e.g. testing, redux, less etc.), and the perhaps naive assumption that straying a bit off the path wouldn't be too much of a problem.
I think I have just about managed to add less using the following webpack.config.dev.js:
//......
module: {
preLoaders: [
{
test: /\.js$/,
loader: 'eslint',
include: paths.appSrc,
}
],
loaders: [
// Process JS with Babel.
{
test: /\.js$/,
include: paths.appSrc,
loader: 'babel',
query: require('./babel.dev')
},
{
test: /\.css$/,
loader: 'style!css!postcss'
},
{
test: /\.less$/,
loader: 'style!css!postcss!less'
},
{
test: /\.json$/,
loader: 'json'
},
//......
}
]
},//.....
I have left the CSS loader in there (perhaps incorrectly) so that I can bring in the react/bootstrap library. Perhaps there is a better way of doing this.
Anyway, I am confused about how to add a pre-processor into webpack.config.prod.js. Here is a snippet (with Facebook's helpful comments):
loaders: [
// Process JS with Babel.
{
test: /\.js$/,
include: paths.appSrc,
loader: 'babel',
query: require('./babel.prod')
},
// The notation here is somewhat confusing.
// "postcss" loader applies autoprefixer to our CSS.
// "css" loader resolves paths in CSS and adds assets as dependencies.
// "style" loader normally turns CSS into JS modules injecting <style>,
// but unlike in development configuration, we do something different.
// `ExtractTextPlugin` first applies the "postcss" and "css" loaders
// (second argument), then grabs the result CSS and puts it into a
// separate file in our build process. This way we actually ship
// a single CSS file in production instead of JS code injecting <style>
// tags. If you use code splitting, however, any async bundles will still
// use the "style" loader inside the async code so CSS from them won't be
// in the main CSS file.
{
test: /\.css$/,
// "?-autoprefixer" disables autoprefixer in css-loader itself:
// https://github.com/webpack/css-loader/issues/281
// We already have it thanks to postcss. We only pass this flag in
// production because "css" loader only enables autoprefixer-powered
// removal of unnecessary prefixes when Uglify plugin is enabled.
// Webpack 1.x uses Uglify plugin as a signal to minify *all* the assets
// including CSS. This is confusing and will be removed in Webpack 2:
// https://github.com/webpack/webpack/issues/283
loader: ExtractTextPlugin.extract('style', 'css?-autoprefixer!postcss')
// Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
},
How can I add a less pre-processor step in a stable and performant way?
For context my index.js imports look as follows:
import React from 'react';
import ReactDOM from 'react-dom';
import 'bootstrap/dist/css/bootstrap.css';
import 'bootstrap/dist/css/bootstrap-theme.css';
import { CommentsSectionContainer } from './components/CommentsSection';
import './index.less';
Install less and less-loader from npm or yarn:
npm install --save-dev less less-loader
Follow this link to install extract-text-webkit-plugin:
https://github.com/webpack/extract-text-webpack-plugin
First you need to add the loader in the loaders array, after css probably makes sense for readability. It will look like this:
{
test: /\.less$/,
loader: ExtractTextPlugin.extract("style-loader", "css-loader!less-loader")
}
Then initialize the plugin in the plugins array:
new ExtractTextPlugin('[name].css')
Thaaaaaat should do it with another yarnpkg start

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