JSS VS css-loader

Most websites those days are SPA applications that render on the front-side. There is also this trend of CSS in JavaScript also knowns as JSS that is debatable (makes everything overcomplicated), but in some specific cases, can be justified and very useful.

> why tf aren't we using JS for styling already

People are and have been for quite a while

https://cssinjs.org/

JSS

It is possible. At its most simple, you could just modify the style property on every element. That's not generally considered best practice, but there are a number of "CSS-in-JS" libraries which streamline the process. The typically generate dynamic CSS classes and apply them to your elements. A big one is JSS.

import React, { useState, useEffect } from "react"; import Amplify, { API, graphqlOperation } from "aws-amplify"; import { createBlog } from "./graphql/mutations"; import { listBlogs } from "./graphql/queries"; import awsExports from "./aws-exports"; import { ListBlogsQuery } from "./API"; Amplify.configure(awsExports); const initialState = { name: "", body: "" }; const App = () => { const [formState, setFormState] = useState(initialState); const [blogs, setBlogs] = useState(); useEffect(() => { fetchBlogs() }, []); const handleInputChange = (event: React.ChangeEvent) => { setFormState({ ...formState, [event.target.name]: event.target.value }); }; const fetchBlogs = async () => { try { const blogData = (await API.graphql(graphqlOperation(listBlogs))) as { data: ListBlogsQuery } setBlogs(blogData.data); } catch (err) { console.log("Error fetching blogs" + err); } }; const addBlog = async () => { try { if (!formState.name || !formState.body) return; const blog = { ...formState }; if (blogs) { await API.graphql(graphqlOperation(createBlog, { input: blog })); await fetchBlogs(); setFormState(initialState); } } catch (err) { console.log("error creating blog: ", err); } }; return (

Amplify Todos

Create Blog {blogs && blogs?.listBlogs?.items?.map((blog, index) => { return (

{blog?.name}

{blog?.body}

); })}

); }; const styles = { container: { width: 400, margin: "0 auto", display: "flex", //real weird issue: https://github.com/cssinjs/jss/issues/1344 flexDirection: "column" as "column", justifyContent: "center", padding: 20, }, todo: { marginBottom: 15 }, input: { border: "none", backgroundColor: "#ddd", marginBottom: 10, padding: 8, fontSize: 18, }, todoName: { fontSize: 20, fontWeight: "bold" }, todoDescription: { marginBottom: 0 }, button: { backgroundColor: "black", color: "white", outline: "none", fontSize: 18, padding: "12px 0px", }, }; export default App;

Material UI v5 brought some amazing updates, but switching from JSS to Emotion had an arguably nasty side-effect: it was no longer as straightforward to group your component styles in classes. Fortunately, a fantastic library emerged that allowed developers to not only reduce the extreme pain from migrating all their classes from v4's makeStyles to emotion, but to also to continue to writing classes in practically the same syntax, with wonderful TS type-safety. This library was tss-react, and it was one of my favorite open source discoveries of 2021.

I started writing a long response, but I want to add that a simple CRA + JSS + TS (named exports only) stack solves or abstracts away most of these issues.

JSS

@fbem/css-loader is very similar to css-loader (and actually a fork of it) and has almost the same set of options and functionality. You can even use it with different style preprocessors by simply chaining loaders together in webpack config. But be sure to pick up if you need them 😏.

Css files need a css loader like https://github.com/webpack-contrib/css-loader. In fact I see you already have 2 css loaders in your normal webpack config. the server config needs those too. Your fronted build and server build will be very similar in that regard.

React comes by default with css module support via https://github.com/webpack-contrib/css-loader, which is stable and not deprecated. (Note that this entirely independent of react)

I have enabled CSS modules within webpack.config in my React application so that I can locally scope CSS files to individual components. I'm also trying to use the TabView component from PrimeReact. When I do so the themes from PrimeReact are not applied. If I create a separate project and do not enable CSS modules the themes apply correctly.

this is technically a feature of css-loader and not of nextjs, next just supports it ootb through their webpack config. iirc its this option you need to customize

const config = { mode: isProdBuild ? 'production' : 'development', devtool: isProdBuild ? 'source-map' : 'cheap-module-eval-source-map', entry: { app: `${SRC_DIR}/index.js`, }, optimization: { minimize: isProdBuild, sideEffects: true, }, context: SRC_DIR, stats: { colors: true, hash: true, timings: true, assets: true, chunks: false, chunkModules: false, modules: false, children: false, warnings: true, }, module: { rules: [ transpileJavaScriptRule(mode), loadWebWorkersRule, loadShadersRule, ], }, resolve: { // Which directories to search when resolving modules modules: [ // Modules specific to this package path.resolve(__dirname, '../node_modules'), // Hoisted Yarn Workspace Modules path.resolve(__dirname, '../../../node_modules'), SRC_DIR, ], // Attempt to resolve these extensions in order. extensions: ['.js', '.jsx', '.json', '*'], // symlinked resources are resolved to their real path, not their symlinked location symlinks: true, }, plugins: [ new webpack.DefinePlugin({ /* Application */ 'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV), 'process.env.DEBUG': JSON.stringify(process.env.DEBUG), 'process.env.APP_CONFIG': JSON.stringify(process.env.APP_CONFIG || ''), 'process.env.PUBLIC_URL': JSON.stringify(process.env.PUBLIC_URL || ''), 'process.env.VERSION_NUMBER': JSON.stringify(PACKAGE.version || ''), 'process.env.BUILD_NUM': JSON.stringify(BUILD_NUM), /* i18n */ 'process.env.USE_LOCIZE': JSON.stringify(process.env.USE_LOCIZE || ''), 'process.env.LOCIZE_PROJECTID': JSON.stringify(process.env.LOCIZE_PROJECTID || ''), 'process.env.LOCIZE_API_KEY': JSON.stringify(process.env.LOCIZE_API_KEY || ''), /* XNAT dev */ 'process.env.XNAT_PROXY': JSON.stringify(process.env.XNAT_PROXY || ''), 'process.env.XNAT_DOMAIN': JSON.stringify(process.env.XNAT_DOMAIN || ''), 'process.env.XNAT_USERNAME': JSON.stringify(process.env.XNAT_USERNAME || ''), 'process.env.XNAT_PASSWORD': JSON.stringify(process.env.XNAT_PASSWORD || ''), }), ], // // Fix: https://github.com/webpack-contrib/css-loader/issues/447#issuecomment-285598881 // // For issue in cornerstone-wado-image-loader // node: { // fs: 'empty', // }, };

One possible non-JSS solution is css-modules supported in css-loader. That requires some setup which may get convoluted if you need CSS preprocessors or SSR.

✨ css loader 💥 jss 🌟 csjs ☄️ aphrodite

Before we start, you should have a minimum knowledge of webpack, you should have css-loader. Along this article, I use nuxt for example, but you can use React or Angular.

The above should work in Create React App out of the box. If you are rolling your own Webpack configuration (may God have mercy on your soul), you'll need to configure modules with a compileType of icss: