remove duplicate sass imports (webpack) - reactjs

I have a big project with a lot of sass files (and all of them import a main sass file with some varibales and classes).
I belive you all know the problem that the file that i am import in all of my css files is duplicate in the main css file after buiding the project.
i tried using ExtractTextPlugin options and plugin that called OptimizeCssAssetsPlugin, and i didnt find solution for this problem.
Here is the plugins array in my webpack prod config:
new ExtractTextPlugin({
filename: "styles.css",
}),
new OptimizeCssAssetsPlugin({
assetNameRegExp: /\.optimize\.css$/g,
cssProcessor: require('cssnano'),
cssProcessorOptions: { safe: true, discardComments: { removeAll: true } },
canPrint: true
}),
anyone know the solution for this problem?
thank you!

Less users are in luck! #import (reference) does exactly what it that:
Use #import (reference) to import external files, but without adding the imported styles to the compiled output unless referenced.
However in Stylus /Sass, there is no direct way to import by reference:
The closest you will get is a silent class / placeholder. These work a little different to how LESS and reference work, you can read more on them here: http://blog.teamtreehouse.com/extending-placeholder-selectors-with-sass
Refernce: Rerernce

Related

A fool-proof tsup config for a React component library

I've never published an NPM package before. All these details to generate a package seem way too complicated to my level. The only tool, that was beginner friendly, that I could find is create-react-library which recommended to switch to tsup instead.
I'm asking here to know if there's a batteries-included, most-cases-met, setup for tsup or any other tool of your recommendation for this kind of project (and I think this is a common scenario):
A React Project
Typed with Typescript
Tested with Jest
No dependencies
Exports React components
Should be public on NPM
If you want most-cases-met, batteries-included way to make a library like that then take a look at dts-cli. It will work but it will definitely be slower than tsup. I myself am in the process of switching a library with about 60 react components from dts-cli to tsup because the build time started taking too long (about a minute) on a MacBook Air M1.
Here is an example setup.
First you need to bundle each component separately. You can use a glob as an entry point in Tsup.
Keep in mind that options that works for Esbuild works for Tsup most of the time.
// tsup.config.ts
defineConfig([
{
clean: true,
sourcemap: true,
tsconfig: path.resolve(__dirname, "./tsconfig.build.json"),
entry: ["./components/core/!(index).ts?(x)"],
format: ["esm"],
outDir: "dist/",
esbuildOptions(options, context) {
// the directory structure will be the same as the source
options.outbase = "./";
},
},
Then you'll want to have a index.ts, for convenience, that expose named exports. This index is sometimes referred as a "barrel" file.
// index.ts
// the actual file is "Button.tsx" but we still want a ".js" here
export { Button } from "./components/core/Button.js";
Notice the .js extension. ESM expects explicit extensions so it's needed in the final build.
Adding the .js doesn't seem to bother TypeScript, which stills correctly recognize the type of "Button" from Button.tsx. At this point I am not sure why it works, but it does.
Transpile this index, without bundling.
// tsup.config.ts
{
clean: true,
sourcemap: true,
tsconfig: path.resolve(__dirname, "./tsconfig.build.json"),
entry: ["index.ts", "./components/core/index.ts"],
bundle: false,
format: ["esm"],
outDir: "dist",
esbuildOptions(options, context) {
options.outbase = "./";
},
},
])
Finally define your package.json as usual:
"sideEffects": false,
"type": "module",
"exports": {
".": "./dist/index.js"
},
sideEffects is a non-standard property targeting application bundlers like Webpack and Rollup.
Setting it to false tells them that the package is safe for tree-shaking.
Now import { Button } from "my-package" should work as you expect, and tree-shaking and dynamic loading at app-level become possible because "Button" is bundled as its own ES module Button.js, and the package is marked as being side-effect free.
This is confirmed by my Webpack Bundle Analyzer in a Next app:
Before (a single bundled index.js):
After (separate files means I can select more precisely my imports):
Final config available here (might be improved in the future)

React component inside Angular app: import scss files

I'm trying to understand how to customize the Angular CLI build process to be able to have React components properly built when they import scss files.
I'm currently able to build an Angular project where some React components are used. There's a lot of material out there that explains how to achieve it (it's pretty simple actually).
I still haven't found an article that points out how to have scss file imports properly resolved in .tsx files though.
For example, if I have this simple React component:
import * as styles from "./styles.scss";
const ReactComponentWithBrokenStyles = () => (
<div className={styles.root}>This div won't have a class</div>
);
export default ReactComponentWithBrokenStyles;
how can I edit the Angular CLI build process to properly add the loaders that would transform the .scss file?
I've found some resources pointing me to using a custom builder instead of the standard builder, which would allow me to provide an extra webpack config file. What I don't understand is how to write the loaders in that file to solve my problem.
The default Angular CLI webpack config already has a loader for .scss files, which need to be transformed and referenced by Angular components, and I don't want to override that... so how can I add a loader just for .scss files that are imported in .tsx files? Is there a way to tell webpack to match files based on siblings in addition to the usual regex?
I guess this is exquisitely a webpack question after all.
Note: using Angular CLI v7 and webpack 4.
The real problem was: I need to distinguish Angular .scss files from React .scss files.
The solution I came up with is centered around using oneOf in Webpack's rule configuration for .scss files, which allows discriminating between files that pass the same test (/\.scss|\.sass$/) in a more fine grained way.
So I've used #angular-builders/custom-webpack as suggested by the link I posted in the question, and I've created this customizer for the standard Angular CLI Webpack configuration:
const reactScssFilesLoaders = [
"style-loader",
{
loader: "css-loader",
options: {
discardDuplicates: true,
importLoaders: 1,
modules: true,
localIdentName: "[name]__[local]___[hash:base64:5]",
},
},
"postcss-loader",
"sass-loader"
];
/**
* Modifies the default Webpack config so that our React components are able to
* import styles from scss files as JS objects
* #param {*} defaultAngularConfig The default Webpack config that comes with the NG Cli
* #param {*} buildOptions The build options (not needed here)
* #returns The adjusted Webpack config
*/
function customizeWebpackConfig(defaultAngularConfig, buildOptions) {
const builtInNgScssFilesRule = defaultAngularConfig.module.rules.find(r => r.test.source.includes("scss"));
if (!builtInNgScssFilesRule) {
throw new Error("WTF?");
}
const angularScssFilesLoaders = builtInNgScssFilesRule.use;
// We only want one top level rule for .scss files, so we need to further test
// We want to leave normal Angular style files to the default loaders, and
// we just want to turn styles into JS code when imported by tsx components
builtInNgScssFilesRule.oneOf = [{
issuer: /\.(tsx)$/,
use: reactScssFilesLoaders
}, {
test: /\.(component)\.(scss)$/,
use: angularScssFilesLoaders
}]
delete builtInNgScssFilesRule.exclude;
delete builtInNgScssFilesRule.use;
return defaultAngularConfig;
}
module.exports = customizeWebpackConfig;
Works like a charm.

Shared component library best practices

I am creating a shareable React component library.
The library contains many components but the end user may only need to use a few of them.
When you bundle code with Webpack (or Parcel or Rollup) it creates one single file with all the code.
For performance reasons I do not want to all that code to be downloaded by the browser unless it is actually used.
Am I right in thinking that I should not bundle the components? Should the bundling be left to the consumer of the components?
Do I leave anything else to the consumer of the components? Do I just transpile the JSX and that's it?
If the same repo contains lots of different components, what should be in main.js?
This is an extremely long answer because this question deserves an extremely long and detailed answer as the "best practice" way is more complicated than just a few-line response.
I've maintained our in-house libraries for 3.5+ years in that time I've settled on two ways I think libraries should be bundled the trade-offs depend on how big your library is and personally we compile both ways to please both subsets of consumers.
Method 1: Create an index.ts file with everything you want to be exposed exported and target rollup at this file as its input. Bundle your entire library into a single index.js file and index.css file; With external dependencies inherited from the consumer project to avoid duplication of library code.
(gist included at bottom of example config)
Pros: Easy to consume as project consumers can import everything from the root relative library path import { Foo, Bar } from "library"
Cons: This will never be tree shakable, and before people say to do this with ESM and it will be tree shakeable. NextJS doesn't support ESM at this current stage and neither do a lot of project setups that's why it's still a good idea to compile this build to just CJS. If someone imports 1 of your components they will get all the CSS and all the javascript for all your components.
Method 2: This is for advanced users: Create a new file for every export and use rollup-plugin-multi-input with the option "preserveModules: true" depending on how what CSS system you're using your also need to make sure that your CSS is NOT merged into a single file but that each CSS file requires(".css") statement is left inside the output file after rollup and that CSS file exists.
Pros: When users import { Foo } from "library/dist/foo" they will
only get the code for Foo, and the CSS for Foo, and nothing more.
Cons: This setup involves the consumer having to handle node_modules
require(".css") statements in their build configuration with NextJS
this is done with next-transpile-modules npm package.
Caveat: We use our own babel plugin you can find it here: https://www.npmjs.com/package/babel-plugin-qubic to allow people to import { Foo, Bar } from "library" and then with babel transform it to...
import { Foo } from "library/dist/export/foo"
import { Bar } from "library/dist/export/bar"
We have multiple rollup configurations where we actually use both methods; so for library consumers who don't care for tree shaking can just do "Foo from "library" and import the single CSS file, and for library consumers who do care for tree shaking and only using critical CSS they can just turn on our babel plugin.
Rollup guide for best practice:
whether you are using typescript or not ALWAYS build with "rollup-plugin-babel": "5.0.0-alpha.1"
Make sure your .babelrc looks like this.
{
"presets": [
["#babel/preset-env", {
"targets": {"chrome": "58", "ie": "11"},
"useBuiltIns": false
}],
"#babel/preset-react",
"#babel/preset-typescript"
],
"plugins": [
["#babel/plugin-transform-runtime", {
"absoluteRuntime": false,
"corejs": false,
"helpers": true,
"regenerator": true,
"useESModules": false,
"version": "^7.8.3"
}],
"#babel/plugin-proposal-class-properties",
"#babel/plugin-transform-classes",
["#babel/plugin-proposal-optional-chaining", {
"loose": true
}]
]
}
And with the babel plugin in rollup looking like this...
babel({
babelHelpers: "runtime",
extensions,
include: ["src/**/*"],
exclude: "node_modules/**",
babelrc: true
}),
And your package.json looking ATLEAST like this:
"dependencies": {
"#babel/runtime": "^7.8.3",
"react": "^16.10.2",
"react-dom": "^16.10.2",
"regenerator-runtime": "^0.13.3"
},
"peerDependencies": {
"react": "^16.12.0",
"react-dom": "^16.12.0",
}
And finally your externals in rollup looking ATLEAST like this.
const makeExternalPredicate = externalArr => {
if (externalArr.length === 0) return () => false;
return id => new RegExp(`^(${externalArr.join('|')})($|/)`).test(id);
};
//... rest of rollup config above external.
external: makeExternalPredicate(Object.keys(pkg.peerDependencies || {}).concat(Object.keys(pkg.dependencies || {}))),
// rest of rollup config below external.
Why?
This will bundle your shit to automatically to inherit
react/react-dom and your other peer/external dependencies from the
consumer project meaning they won't be duplicated in your bundle.
This will bundle to ES5
This will automatically require("..") in all the babel helper functions for objectSpread, classes, etc FROM the consumer project which will wipe another 15-25KB from your bundle size and mean that the helper functions for objectSpread won't be duplicated in your library output + the consuming projects bundled output.
Async functions will still work
externals will match anything that starts with that peer-dependency suffix i.e babel-helpers will match external for babel-helpers/helpers/object-spread
Finally here is a gist for an example single index.js file output rollup config file.
https://gist.github.com/ShanonJackson/deb65ebf5b2094b3eac6141b9c25a0e3
Where the target src/export/index.ts looks like this...
export { Button } from "../components/Button/Button";
export * from "../components/Button/Button.styles";
export { Checkbox } from "../components/Checkbox/Checkbox";
export * from "../components/Checkbox/Checkbox.styles";
export { DatePicker } from "../components/DateTimePicker/DatePicker/DatePicker";
export { TimePicker } from "../components/DateTimePicker/TimePicker/TimePicker";
export { DayPicker } from "../components/DayPicker/DayPicker";
// etc etc etc
Let me know if you experience any problems with babel, rollup, or have any questions about bundling/libraries.
When you bundle code with Webpack (or Parcel or Rollup) it creates one single file with all the code.
For performance reasons I do not want to all that code to be downloaded by the browser unless it is actually used
It's possible to have separate files generated for each component. Webpack has such ability by defining multiple entries and outputs. Let's say you have the following structure of a project
- my-cool-react-components
- src // Folder contains all source code
- index.js
- componentA.js
- componentB.js
- ...
- lib // Folder is generated when build
- index.js // Contains components all together
- componentA.js
- componentB.js
- ...
Webpack file would look something like this
const path = require('path');
module.exports = {
entry: {
index: './src/index.js',
componentA: './src/componentA.js',
componentB: './src/componentB.js',
},
output: {
filename: '[name].js',
path: path.resolve(__dirname, 'lib'),
},
};
More info on "code splitting" is here in Webpack docs
If the same repo contains lots of different components, what should be in main.js?
There is a single field in package.json file named main, it's good to put its value lib/index.js according to the project structure above. And in index.js file have all components exported. In case consumer wants to use single component it's reachable by simply doing
const componentX = require('my-cool-react-components/lib/componentX');
Am I right in thinking that I should not bundle the components? Should the bundling be left to the consumer of the components? Do I leave anything else to the consumer of the components? Do I just transpile the JSX and that's it?
Well, it's up to you. I've found that some React libraries are published in original way, others - are in bundled way. If you need some build process, then define it and export bundled version.
Hope, all your questions are answered :)
You can split your components like lodash is doing for their methods.
What you probably have is separate components that you could allow importing separately or through the main component.
Then the consumer could import the whole package
import {MyComponent} from 'my-components';
or its individual parts
import MyComponent from 'my-components/my-component';
Consumers will create their own bundles based on the components they import. That should prevent your whole bundle being downloaded.
You should take a look at Bit, I think this is a good solution to share, reuse and visualize components.
It is very easy to setup. You can install your bit library or just a component with:
npm i #bit/bit.your-library.components.buttons
Then you can import the component in your app with:
import Button3 from '#bit/bit.your-library.components.buttons';
The good part is that you don't have to worry about configuring Webpack and all that jazz. Bit even supports the versioning of your components. This example shows a title-list react component so you can take a look if this meets your requirements or not
There is a configuration in webpack to create chunk files. To start with it will create the main bundle into multiple chunks and get it loaded as when required. if your project has well structured modules, it will not load any code which is not required.

Cannot import local fonts with TypeScript

I am trying to import font files on React with TypeScript project, but it doesn't recognize it as a font file, but instead, it looks at it as a module
Folder structure:
In my index.tsx file, I imported the font I need, and exported Font constant:
import helveticaNeueLightWoff from './HelveticaNeueW02-45Ligh.woff';
import helveticaNeueLightWoff2 from './HelveticaNeueW02-45Ligh.woff2';
import helveticaNeueMediumWoff from './HelveticaNeueW02-67MdCn.woff';
import helveticaNeueMediumWoff2 from './HelveticaNeueW02-67MdCn.woff2';
import helveticaNeueBoldWoff from './HelveticaNeueW02-75Bold.woff';
import helveticaNeueBoldWoff2 from './HelveticaNeueW02-75Bold.woff2';
import helveticaNeueBoldCnWoff from './HelveticaNeueW02-77BdCn.woff';
import helveticaNeueBoldCnWoff2 from './HelveticaNeueW02-77BdCn.woff2';
const Fonts = {
helveticaNeueLightWoff,
helveticaNeueLightWoff2,
helveticaNeueMediumWoff,
helveticaNeueMediumWoff2,
helveticaNeueBoldWoff,
helveticaNeueBoldWoff2,
helveticaNeueBoldCnWoff,
helveticaNeueBoldCnWoff2,
};
export default Fonts;
I use url-loader(I also tried with file-loader). This is my webpack.config.ts
{
test: /\.(woff|woff2)(\?v=\d+\.\d+\.\d+)?$/,
use: {
loader: 'url-loader',
options: {
// Limit at 50k. Above that it emits separate files
limit: 50000,
// url-loader sets mimetype if it's passed.
// Without this it derives it from the file extension
mimetype: 'application/font-woff',
// Output below fonts directory
name: './fonts/[name].[ext]',
},
},
},
This is the error I get: Cannot find module './HelveticaNeueW02-45Ligh.woff'
What could be the cause of this problem?
You need to declare the font file formats as modules so that TypeScript can parse them correctly.
create a fonts.d.ts file and add the following to it
declare module '*.woff';
declare module '*.woff2';
It tells TypeScript that the font filetypes are valid import modules.
The "d.ts" file format is used to provide typescript type information about an API that's written in JavaScript, or the shape of the third party imports.
Make sure that the types file is considered in the include section in tsconfig.json. A nice approach is to have a root typings directory in your project, then append typings/**/*.d.ts on include.
Completion of the previous answer for expo user who would face a similar issue :
I faced the same issue, and declaring the module was enough to import fonts but not to actually load these.
I was using expo-font, and Typescript was complaining about the type of the result. To make it work, I created the same file with the following content :
declare module "*.ttf" {
const value: import("expo-font").FontSource;
export default value;
}
This tells that the module imported will have the type FontSource that comes from expo-font library. I was then able to load my font :)

Flow seems not to respect include option?

I've setup my React project with a folder for common components I want to import directly.
src/
---components/
---common/
---/TextInput
---/TabSelector
Full folder structure from root
Each of these folders in common have a index.jsx (and other resources such as style etc) with and export default <name> statement.
So my webpack config has the following configuration:
resolve: {
modulesDirectories: [
'node_modules',
myCommonComponentsPath
]
}
which allows direct imports: import TextInput from 'TextInput'
Trying to add this to .flowconfig (according to flow's documentiation) is not working though:
[include]
./node_modules/
<PROJECT_ROOT>/src/components/common
This works with webpacks resolver (components load and work) but flow gives the following error:
9: import TextInput from 'TextInput';
^^^^^^^^^^^ TextInput. Required module not found
Any help would be appreciated.
How do I resolve this?
You need to use the module.system.node.resolve_dirname setting, which is different from the include setting. Since you are telling Webpack a new place to find modules, you also need to tell Flow about that new place.
[options]
module.system.node.resolve_dirname=node_modules
module.system.node.resolve_dirname=src/components/common
The paths are relative to the location of your '.flowconfig' file.

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