1 | # babel-plugin-react-css-modules
|
2 |
|
3 | [![Travis build status](http://img.shields.io/travis/gajus/babel-plugin-react-css-modules/master.svg?style=flat-square)](https://travis-ci.org/gajus/babel-plugin-react-css-modules)
|
4 | [![NPM version](http://img.shields.io/npm/v/babel-plugin-react-css-modules.svg?style=flat-square)](https://www.npmjs.org/package/babel-plugin-react-css-modules)
|
5 | [![Canonical Code Style](https://img.shields.io/badge/code%20style-canonical-blue.svg?style=flat-square)](https://github.com/gajus/canonical)
|
6 | [![Gitter](https://img.shields.io/gitter/room/babel-plugin-react-css-modules/Lobby.svg?style=flat-square)](https://gitter.im/babel-plugin-react-css-modules/Lobby)
|
7 | [![Twitter Follow](https://img.shields.io/twitter/follow/kuizinas.svg?style=social&label=Follow)](https://twitter.com/kuizinas)
|
8 |
|
9 | <img src='./.README/babel-plugin-react-css-modules.png' height='150' />
|
10 |
|
11 | Transforms `styleName` to `className` using compile time [CSS module](#css-modules) resolution.
|
12 |
|
13 | In contrast to [`react-css-modules`](https://github.com/gajus/react-css-modules), `babel-plugin-react-css-modules` has a lot smaller performance overhead (0-10% vs +50%; see [Performance](#performance)) and a lot smaller size footprint (less than 2kb vs 17kb react-css-modules + lodash dependency).
|
14 |
|
15 | * [CSS Modules](#css-modules)
|
16 | * [Difference from `react-css-modules`](#difference-from-react-css-modules)
|
17 | * [Performance](#performance)
|
18 | * [How does it work?](#how-does-it-work)
|
19 | * [Conventions](#conventions)
|
20 | * [Anonymous reference](#anonymous-reference)
|
21 | * [Named reference](#named-reference)
|
22 | * [Configuration](#configuration)
|
23 | * [Configurate syntax loaders](#configurate-syntax-loaders)
|
24 | * [Installation](#installation)
|
25 | * [Demo](#demo)
|
26 | * [Example transpilations](#example-transpilations)
|
27 | * [Anonymous `styleName` resolution](#anonymous-stylename-resolution)
|
28 | * [Named `styleName` resolution](#named-stylename-resolution)
|
29 | * [Runtime `styleName` resolution](#runtime-stylename-resolution)
|
30 | * [Limitations](#limitations)
|
31 | * [Have a question or want to suggest an improvement?](#have-a-question-or-want-to-suggest-an-improvement)
|
32 | * [FAQ](#faq)
|
33 | * [How to reference multiple CSS modules?](#how-to-reference-multiple-css-modules)
|
34 | * [How to live reload the CSS?](#hot-to-live-reload-the-css)
|
35 |
|
36 | ## CSS Modules
|
37 |
|
38 | [CSS Modules](https://github.com/css-modules/css-modules) are awesome! If you are not familiar with CSS Modules, it is a concept of using a module bundler such as [webpack](http://webpack.github.io/docs/) to load CSS scoped to a particular document. CSS module loader will generate a unique name for each CSS class at the time of loading the CSS document ([Interoperable CSS](https://github.com/css-modules/icss) to be precise). To see CSS Modules in practice, [webpack-demo](https://css-modules.github.io/webpack-demo/).
|
39 |
|
40 | In the context of React, CSS Modules look like this:
|
41 |
|
42 | ```js
|
43 | import React from 'react';
|
44 | import styles from './table.css';
|
45 |
|
46 | export default class Table extends React.Component {
|
47 | render () {
|
48 | return <div className={styles.table}>
|
49 | <div className={styles.row}>
|
50 | <div className={styles.cell}>A0</div>
|
51 | <div className={styles.cell}>B0</div>
|
52 | </div>
|
53 | </div>;
|
54 | }
|
55 | }
|
56 |
|
57 | ```
|
58 |
|
59 | Rendering the component will produce a markup similar to:
|
60 |
|
61 | ```js
|
62 | <div class="table__table___32osj">
|
63 | <div class="table__row___2w27N">
|
64 | <div class="table__cell___1oVw5">A0</div>
|
65 | <div class="table__cell___1oVw5">B0</div>
|
66 | </div>
|
67 | </div>
|
68 |
|
69 | ```
|
70 |
|
71 | and a corresponding CSS file that matches those CSS classes.
|
72 |
|
73 | Awesome!
|
74 |
|
75 | However, there are several several disadvantages of using CSS modules this way:
|
76 |
|
77 | * You have to use `camelCase` CSS class names.
|
78 | * You have to use `styles` object whenever constructing a `className`.
|
79 | * Mixing CSS Modules and global CSS classes is cumbersome.
|
80 | * Reference to an undefined CSS Module resolves to `undefined` without a warning.
|
81 |
|
82 | `babel-plugin-react-css-modules` automates loading of CSS Modules using `styleName` property, e.g.
|
83 |
|
84 | ```js
|
85 | import React from 'react';
|
86 | import './table.css';
|
87 |
|
88 | export default class Table extends React.Component {
|
89 | render () {
|
90 | return <div styleName='table'>
|
91 | <div styleName='row'>
|
92 | <div styleName='cell'>A0</div>
|
93 | <div styleName='cell'>B0</div>
|
94 | </div>
|
95 | </div>;
|
96 | }
|
97 | }
|
98 |
|
99 | ```
|
100 |
|
101 | Using `babel-plugin-react-css-modules`:
|
102 |
|
103 | * You are not forced to use the `camelCase` naming convention.
|
104 | * You do not need to refer to the `styles` object every time you use a CSS Module.
|
105 | * There is clear distinction between global CSS and CSS modules, e.g.
|
106 |
|
107 | ```js
|
108 | <div className='global-css' styleName='local-module'></div>
|
109 | ```
|
110 |
|
111 | <!--
|
112 | * You are warned when `styleName` refers to an undefined CSS Module ([`errorWhenNotFound`](#errorwhennotfound) option).
|
113 | * You can enforce use of a single CSS module per `ReactElement` ([`allowMultiple`](#allowmultiple) option).
|
114 | -->
|
115 |
|
116 | ## Difference from `react-css-modules`
|
117 |
|
118 | [`react-css-modules`](https://github.com/gajus/react-css-modules) introduced a convention of using `styleName` attribute to reference [CSS module](https://github.com/css-modules/css-modules). `react-css-modules` is a higher-order [React](https://facebook.github.io/react/) component. It is using the `styleName` value to construct the `className` value at the run-time. This abstraction frees a developer from needing to reference the imported styles object when using CSS modules ([What's the problem?](https://github.com/gajus/react-css-modules#whats-the-problem)). However, this approach has a measurable performance penalty (see [Performance](#performance)).
|
119 |
|
120 | `babel-plugin-react-css-modules` solves the developer experience problem without impacting the performance.
|
121 |
|
122 | ## Performance
|
123 |
|
124 | The important metric here is the "Difference from the base benchmark". "base" is defined as using React with hardcoded `className` values. The lesser the difference, the bigger the performance impact.
|
125 |
|
126 | > Note:
|
127 | > This benchmark suite does not include a scenario when `babel-plugin-react-css-modules` can statically construct a literal value at the build time.
|
128 | > If a literal value of the `className` is constructed at the compile time, the performance is equal to the base benchmark.
|
129 |
|
130 | |Name|Operations per second (relative margin of error)|Sample size|Difference from the base benchmark|
|
131 | |---|---|---|---|
|
132 | |Using `className` (base)|9551 (±1.47%)|587|-0%|
|
133 | |`react-css-modules`|5914 (±2.01%)|363|-61%|
|
134 | |`babel-plugin-react-css-modules` (runtime, anonymous)|9145 (±1.94%)|540|-4%|
|
135 | |`babel-plugin-react-css-modules` (runtime, named)|8786 (±1.59%)|527|-8%|
|
136 |
|
137 | > Platform info:
|
138 | >
|
139 | > * Darwin 16.1.0 x64
|
140 | > * Node.JS 7.1.0
|
141 | > * V8 5.4.500.36
|
142 | > * NODE_ENV=production
|
143 | > * Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz × 8
|
144 |
|
145 | View the [./benchmark](./benchmark).
|
146 |
|
147 | Run the benchmark:
|
148 |
|
149 | ```bash
|
150 | git clone git@github.com:gajus/babel-plugin-react-css-modules.git
|
151 | cd ./babel-plugin-react-css-modules
|
152 | npm install
|
153 | npm run build
|
154 | cd ./benchmark
|
155 | npm install
|
156 | NODE_ENV=production ./test
|
157 | ```
|
158 |
|
159 | ## How does it work?
|
160 |
|
161 | 1. Builds index of all stylesheet imports per file (imports of files with `.css` or `.scss` extension).
|
162 | 1. Uses [postcss](https://github.com/postcss/postcss) to parse the matching CSS files.
|
163 | 1. Iterates through all [JSX](https://facebook.github.io/react/docs/jsx-in-depth.html) element declarations.
|
164 | 1. Parses the `styleName` attribute value into anonymous and named CSS module references.
|
165 | 1. Finds the CSS class name matching the CSS module reference:
|
166 | * If `styleName` value is a string literal, generates a string literal value.
|
167 | * If `styleName` value is a [`jSXExpressionContainer`](https://github.com/babel/babel/tree/master/packages/babel-types#jsxexpressioncontainer), uses a helper function ([`getClassName`](./src/getClassName.js)) to construct the `className` value at the runtime.
|
168 | 1. Removes the `styleName` attribute from the element.
|
169 | 1. Appends the resulting `className` to the existing `className` value (creates `className` attribute if one does not exist).
|
170 |
|
171 | ## Configuration
|
172 |
|
173 | Configure the options for the plugin within your `.babelrc` as follows:
|
174 |
|
175 | ```json
|
176 | {
|
177 | "plugins": [
|
178 | ["react-css-modules", {
|
179 | "option": "value"
|
180 | }]
|
181 | ]
|
182 | }
|
183 |
|
184 | ```
|
185 |
|
186 | ### Options
|
187 |
|
188 | |Name|Type|Description|Default|
|
189 | |---|---|---|---|
|
190 | |`context`|`string`|Must match webpack [`context`](https://webpack.github.io/docs/configuration.html#context) configuration. [`css-loader`](https://github.com/webpack/css-loader) inherits `context` values from webpack. Other CSS module implementations might use different context resolution logic.|`process.cwd()`|
|
191 | |`exclude`|`string`|A RegExp that will exclude otherwise included files e.g., to exclude all styles from node_modules `exclude: 'node_modules'`|
|
192 | |`filetypes`|`?FiletypesConfigurationType`|Configure [postcss syntax loaders](https://github.com/postcss/postcss#syntaxes) like sugerss, LESS and SCSS and extra plugins for them. ||
|
193 | |`generateScopedName`|`?GenerateScopedNameConfigurationType`|Refer to [Generating scoped names](https://github.com/css-modules/postcss-modules#generating-scoped-names)|`[path]___[name]__[local]___[hash:base64:5]`|
|
194 | |`removeImport`|`boolean`|Remove the matching style import. This option is used to enable server-side rendering.|`false`|
|
195 | |`webpackHotModuleReloading`|`boolean`|Enables hot reloading of CSS in webpack|`false`|
|
196 | |`handleMissingStyleName`|`"throw"`, `"warn"`, `"ignore"`|Determines what should be done for undefined CSS modules (using a `styleName` for which there is no CSS module defined). Setting this option to `"ignore"` is equivalent to setting `errorWhenNotFound: false` in [react-css-modules](https://github.com/gajus/react-css-modules#errorwhennotfound). |`"throw"`|
|
197 |
|
198 | Missing a configuration? [Raise an issue](https://github.com/gajus/babel-plugin-react-css-modules/issues/new?title=New%20configuration:).
|
199 |
|
200 | > Note:
|
201 | > The default configuration should work out of the box with the [css-loader](https://github.com/webpack/css-loader).
|
202 |
|
203 | #### Option types (flow)
|
204 |
|
205 | ```js
|
206 | type FiletypeOptionsType = {|
|
207 | +syntax: string,
|
208 | +plugins?: $ReadOnlyArray<string>
|
209 | |};
|
210 |
|
211 | type FiletypesConfigurationType = {
|
212 | [key: string]: FiletypeOptionsType
|
213 | };
|
214 |
|
215 | type GenerateScopedNameType = (localName: string, resourcePath: string) => string;
|
216 |
|
217 | type GenerateScopedNameConfigurationType = GenerateScopedNameType | string;
|
218 |
|
219 | ```
|
220 |
|
221 | ### Configurate syntax loaders
|
222 |
|
223 | To add support for different CSS syntaxes (e.g. SCSS), perform the following two steps:
|
224 |
|
225 | 1. Add the [postcss syntax loader](https://github.com/postcss/postcss#syntaxes) as a development dependency:
|
226 |
|
227 | ```bash
|
228 | npm install postcss-scss --save-dev
|
229 | ```
|
230 |
|
231 | 2. Add a filetype syntax mapping to the Babel plugin configuration
|
232 |
|
233 | ```json
|
234 | "filetypes": {
|
235 | ".scss": {
|
236 | "syntax": "postcss-scss"
|
237 | }
|
238 | }
|
239 | ```
|
240 |
|
241 | And optionaly specify extra plugins
|
242 |
|
243 | ```json
|
244 | "filetypes": {
|
245 | ".scss": {
|
246 | "syntax": "postcss-scss",
|
247 | "plugins": ["postcss-nested"]
|
248 | }
|
249 | }
|
250 | ```
|
251 |
|
252 | ## Installation
|
253 |
|
254 | When `babel-plugin-react-css-modules` cannot resolve CSS module at a compile time, it imports a helper function (read [Runtime `styleName` resolution](#runtime-stylename-resolution)). Therefore, you must install `babel-plugin-react-css-modules` as a direct dependency of the project.
|
255 |
|
256 | ```bash
|
257 | npm install babel-plugin-react-css-modules --save
|
258 | ```
|
259 |
|
260 | ### Demo
|
261 |
|
262 | ```bash
|
263 | git clone git@github.com:gajus/babel-plugin-react-css-modules.git
|
264 | cd ./babel-plugin-react-css-modules/demo
|
265 | npm install
|
266 | webpack-dev-server
|
267 | ```
|
268 |
|
269 | ```bash
|
270 | open http://localhost:8080/
|
271 | ```
|
272 |
|
273 | ## Conventions
|
274 |
|
275 | ### Anonymous reference
|
276 |
|
277 | Anonymous reference can be used when there is only one stylesheet import.
|
278 |
|
279 | Format: `CSS module name`.
|
280 |
|
281 | Example:
|
282 |
|
283 | ```js
|
284 | import './foo1.css';
|
285 |
|
286 | // Imports "a" CSS module from ./foo1.css.
|
287 | <div styleName="a"></div>;
|
288 | ```
|
289 |
|
290 | ### Named reference
|
291 |
|
292 | Named reference is used to refer to a specific stylesheet import.
|
293 |
|
294 | Format: `[name of the import].[CSS module name]`.
|
295 |
|
296 | Example:
|
297 |
|
298 | ```js
|
299 | import foo from './foo1.css';
|
300 | import bar from './bar1.css';
|
301 |
|
302 | // Imports "a" CSS module from ./foo1.css.
|
303 | <div styleName="foo.a"></div>;
|
304 |
|
305 | // Imports "a" CSS module from ./bar1.css.
|
306 | <div styleName="bar.a"></div>;
|
307 | ```
|
308 |
|
309 | ## Example transpilations
|
310 |
|
311 | ### Anonymous `styleName` resolution
|
312 |
|
313 | When `styleName` is a literal string value, `babel-plugin-react-css-modules` resolves the value of `className` at the compile time.
|
314 |
|
315 | Input:
|
316 |
|
317 | ```js
|
318 | import './bar.css';
|
319 |
|
320 | <div styleName="a"></div>;
|
321 |
|
322 | ```
|
323 |
|
324 | Output:
|
325 |
|
326 | ```js
|
327 | import './bar.css';
|
328 |
|
329 | <div className="bar___a"></div>;
|
330 |
|
331 | ```
|
332 |
|
333 | ### Named `styleName` resolution
|
334 |
|
335 | When a file imports multiple stylesheets, you must use a [named reference](#named-reference).
|
336 |
|
337 | > Have suggestions for an alternative behaviour?
|
338 | > [Raise an issue](https://github.com/gajus/babel-plugin-react-css-modules/issues/new?title=Suggestion%20for%20alternative%20handling%20of%20multiple%20stylesheet%20imports) with your suggestion.
|
339 |
|
340 | Input:
|
341 |
|
342 | ```js
|
343 | import foo from './foo1.css';
|
344 | import bar from './bar1.css';
|
345 |
|
346 | <div styleName="foo.a"></div>;
|
347 | <div styleName="bar.a"></div>;
|
348 | ```
|
349 |
|
350 | Output:
|
351 |
|
352 | ```js
|
353 | import foo from './foo1.css';
|
354 | import bar from './bar1.css';
|
355 |
|
356 | <div className="foo___a"></div>;
|
357 | <div className="bar___a"></div>;
|
358 |
|
359 | ```
|
360 |
|
361 | ### Runtime `styleName` resolution
|
362 |
|
363 | When the value of `styleName` cannot be determined at the compile time, `babel-plugin-react-css-modules` inlines all possible styles into the file. It then uses [`getClassName`](https://github.com/gajus/babel-plugin-react-css-modules/blob/master/src/getClassName.js) helper function to resolve the `styleName` value at the runtime.
|
364 |
|
365 | Input:
|
366 |
|
367 | ```js
|
368 | import './bar.css';
|
369 |
|
370 | <div styleName={Math.random() > .5 ? 'a' : 'b'}></div>;
|
371 |
|
372 | ```
|
373 |
|
374 | Output:
|
375 |
|
376 | ```js
|
377 | import _getClassName from 'babel-plugin-react-css-modules/dist/browser/getClassName';
|
378 | import foo from './bar.css';
|
379 |
|
380 | const _styleModuleImportMap = {
|
381 | foo: {
|
382 | a: 'bar__a',
|
383 | b: 'bar__b'
|
384 | }
|
385 | };
|
386 |
|
387 | <div styleName={_getClassName(Math.random() > .5 ? 'a' : 'b', _styleModuleImportMap)}></div>;
|
388 |
|
389 | ```
|
390 |
|
391 | ## Limitations
|
392 |
|
393 | * [Establish a convention for extending the styles object at the runtime](https://github.com/gajus/babel-plugin-react-css-modules/issues/1)
|
394 |
|
395 | ## Have a question or want to suggest an improvement?
|
396 |
|
397 | * Have a technical questions? [Ask on Stack Overflow.](http://stackoverflow.com/questions/ask?tags=babel-plugin-react-css-modules)
|
398 | * Have a feature suggestion or want to report an issue? [Raise an issues.](https://github.com/gajus/babel-plugin-react-css-modules/issues)
|
399 | * Want to say hello to other `babel-plugin-react-css-modules` users? [Chat on Gitter.](https://gitter.im/babel-plugin-react-css-modules)
|
400 |
|
401 | ## FAQ
|
402 |
|
403 | ### How to reference multiple CSS modules?
|
404 |
|
405 | `react-css-modules` had an option [`allowMultiple`](https://github.com/gajus/react-css-modules#allowmultiple). `allowMultiple` allows multiple CSS module names in a `styleName` declaration, e.g.
|
406 |
|
407 | ```js
|
408 | <div styleName='foo bar' />
|
409 | ```
|
410 |
|
411 | This behaviour is enabled by default in `babel-plugin-react-css-modules`.
|
412 |
|
413 | ## How to live reload the CSS?
|
414 |
|
415 | `babel-plugin-react-css-modules` utilises webpack [Hot Module Replacement](https://webpack.github.io/docs/hot-module-replacement.html) (HMR) to live reload the CSS.
|
416 |
|
417 | To enable live reloading of the CSS:
|
418 |
|
419 | * Enable [`webpackHotModuleReloading`](#configuration) `babel-plugin-react-css-modules` configuration.
|
420 | * Configure `webpack` to use HMR. Use [`--hot`](https://webpack.github.io/docs/webpack-dev-server.html) option if you are using `webpack-dev-server`.
|
421 | * Use [`style-loader`](https://github.com/webpack/style-loader) to load the style sheets.
|
422 |
|
423 | > Note:
|
424 | >
|
425 | > This enables live reloading of the CSS. To enable HMR of the React components, refer to the [Hot Module Replacement - React](https://webpack.js.org/guides/hmr-react/) guide.
|
426 |
|
427 | > Note:
|
428 | >
|
429 | > This is a [webpack](https://webpack.github.io/) specific option. If you are using `babel-plugin-react-css-modules` in a different setup and require CSS live reloading, raise an issue describing your setup.
|