146 lines
4.1 KiB
Markdown
146 lines
4.1 KiB
Markdown
# PostCSS Focus Visible [<img src="https://postcss.github.io/postcss/logo.svg" alt="PostCSS Logo" width="90" height="90" align="right">][PostCSS]
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[<img alt="npm version" src="https://img.shields.io/npm/v/postcss-focus-visible.svg" height="20">][npm-url] [<img alt="CSS Standard Status" src="https://cssdb.org/images/badges/focus-visible-pseudo-class.svg" height="20">][css-url] [<img alt="Build Status" src="https://github.com/csstools/postcss-plugins/workflows/test/badge.svg" height="20">][cli-url] [<img alt="Discord" src="https://shields.io/badge/Discord-5865F2?logo=discord&logoColor=white">][discord]
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[PostCSS Focus Visible] lets you use the `:focus-visible` pseudo-class in CSS,
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following the [Selectors Level 4 specification].
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To use this feature you need to do two things :
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- add the [PostCSS plugin](#usage) that transforms the selector into a class or attribute
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- add the [focus-visible polyfill] that sets the attribute or class on elements in a browser
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[](https://caniuse.com/#feat=css-focus-visible)
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```css
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```pcss
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:focus:not(:focus-visible) {
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outline: none;
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}
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/* becomes */
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:focus:not(.focus-visible).js-focus-visible, .js-focus-visible :focus:not(.focus-visible) {
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outline: none;
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}
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:focus:not(:focus-visible) {
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outline: none;
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}
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```
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[PostCSS Focus Visible] duplicates rules using the `:focus-visible` pseudo-class
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with a `.focus-visible` class selector, the same selector used by the
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[focus-visible polyfill].
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## Usage
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Add [PostCSS Focus Visible] to your project:
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```bash
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npm install postcss postcss-focus-visible --save-dev
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```
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Use it as a [PostCSS] plugin:
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```js
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const postcss = require('postcss');
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const postcssFocusVisible = require('postcss-focus-visible');
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postcss([
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postcssFocusVisible(/* pluginOptions */)
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]).process(YOUR_CSS /*, processOptions */);
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```
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[PostCSS Focus Visible] runs in all Node environments, with special
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instructions for:
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- [Node](INSTALL.md#node)
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- [PostCSS CLI](INSTALL.md#postcss-cli)
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- [PostCSS Load Config](INSTALL.md#postcss-load-config)
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- [Webpack](INSTALL.md#webpack)
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- [Next.js](INSTALL.md#nextjs)
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- [Gulp](INSTALL.md#gulp)
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- [Grunt](INSTALL.md#grunt)
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## Options
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### preserve
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The `preserve` option determines whether the original notation
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is preserved. By default, it is preserved.
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```js
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postcssFocusVisible({ preserve: false })
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```
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```pcss
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:focus:not(:focus-visible) {
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outline: none;
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}
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/* becomes */
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:focus:not(.focus-visible).js-focus-visible, .js-focus-visible :focus:not(.focus-visible) {
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outline: none;
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}
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```
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### replaceWith
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The `replaceWith` option defines the selector to replace `:focus-visible`. By
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default, the replacement selector is `.focus-visible`.
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```js
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postcssFocusVisible({ replaceWith: '[data-focus-visible-added]' })
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```
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```pcss
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:focus:not(:focus-visible) {
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outline: none;
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}
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/* becomes */
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<example.preserve-true.expect.css>
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```
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Note that if you want to keep using [focus-visible polyfill], the only
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acceptable value would be `[data-focus-visible-added]`,
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given that the polyfill does not support arbitrary values.
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### disablePolyfillReadyClass
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The `disablePolyfillReadyClass` option determines if selectors are prefixed with an indicator class.
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This class is only set on your document if the polyfill loads and is needed.
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By default this option is `false`.
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Set this to `true` to prevent the class from being added.
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```js
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postcssFocusVisible({ disablePolyfillReadyClass: true })
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```
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```pcss
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:focus:not(:focus-visible) {
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outline: none;
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}
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/* becomes */
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:focus:not(.focus-visible) {
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outline: none;
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}
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:focus:not(:focus-visible) {
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outline: none;
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}
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```
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[cli-url]: https://github.com/csstools/postcss-plugins/actions/workflows/test.yml?query=workflow/test
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[css-url]: https://cssdb.org/#focus-visible-pseudo-class
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[discord]: https://discord.gg/bUadyRwkJS
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[npm-url]: https://www.npmjs.com/package/postcss-focus-visible
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[PostCSS]: https://github.com/postcss/postcss
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[PostCSS Focus Visible]: https://github.com/csstools/postcss-plugins/tree/main/plugins/postcss-focus-visible
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[Selectors Level 4 specification]: https://www.w3.org/TR/selectors-4/#the-focus-visible-pseudo
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[focus-visible polyfill]: https://github.com/WICG/focus-visible
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