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https://github.com/csstools/postcss-env-function
Use env() variables in CSS
https://github.com/csstools/postcss-env-function
Last synced: 4 months ago
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Use env() variables in CSS
- Host: GitHub
- URL: https://github.com/csstools/postcss-env-function
- Owner: csstools
- License: cc0-1.0
- Archived: true
- Created: 2017-12-22T22:17:11.000Z (about 7 years ago)
- Default Branch: main
- Last Pushed: 2021-12-16T12:38:49.000Z (about 3 years ago)
- Last Synced: 2024-04-14T05:31:41.202Z (10 months ago)
- Language: JavaScript
- Homepage: https://github.com/csstools/postcss-plugins/tree/main/plugins/postcss-env-function
- Size: 249 KB
- Stars: 54
- Watchers: 9
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE.md
Awesome Lists containing this project
README
# PostCSS Environment Variables [
][postcss]
[
][npm-url]
[
][css-url]
[
][cli-url]
[
][git-url]
[PostCSS Environment Variables] lets you use `env()` variables in CSS, following the [CSS Environment Variables] specification.
```pcss
@media (max-width: env(--branding-small)) {
body {
padding: env(--branding-padding);
}
}
/* becomes */
@media (min-width: 600px) {
body {
padding: 20px;
}
}
/* when the `importFrom` option is: {
"environmentVariables": {
"--branding-small": "600px",
"--branding-padding": "20px"
}
} */
```
## Usage
Add [PostCSS Environment Variables] to your project:
```bash
npm install postcss postcss-env-function --save-dev
```
Use [PostCSS Environment Variables] to process your CSS:
```js
const postcssEnvFunction = require('postcss-env-function')
postcssEnvFunction.process(YOUR_CSS /*, processOptions, pluginOptions */)
```
Or use it as a [PostCSS] plugin:
```js
const postcss = require('postcss')
const postcssEnvFunction = require('postcss-env-function')
postcss([
postcssEnvFunction(/* pluginOptions */)
]).process(YOUR_CSS /*, processOptions */)
```
[PostCSS Environment Variables] runs in all Node environments, with special instructions for:
| [Node](INSTALL.md#node) | [PostCSS CLI](INSTALL.md#postcss-cli) | [Webpack](INSTALL.md#webpack) | [Create React App](INSTALL.md#create-react-app) | [Gulp](INSTALL.md#gulp) | [Grunt](INSTALL.md#grunt) |
| --- | --- | --- | --- | --- | --- |
## Options
### importFrom
The `importFrom` option specifies sources where Environment Variables can be imported from, which might be JS and JSON files, functions, and directly passed objects.
```js
postcssEnvFunction({
importFrom: 'path/to/file.js' /* module.exports = {
environmentVariables: {
'--branding-padding': '20px',
'--branding-small': '600px'
}
} */
})
```
```pcss
@media (max-width: env(--branding-small)) {
body {
padding: env(--branding-padding);
}
}
/* becomes */
@media (min-width: 600px) {
body {
padding: 20px;
}
}
```
Multiple sources can be passed into this option, and they will be parsed in the order they are received. JavaScript files, JSON files, functions, and objects will need to namespace Custom Properties using the `environmentVariables` or `environment-variables` key.
```js
postcssEnvFunction({
importFrom: [
/* Import from a CommonJS file:
module.exports = {
environmentVariables: {
'--branding-padding': '20px'
}
} */
'path/to/file.js',
/* Import from a JSON file:
{
"environment-variables": {
"--branding-padding": "20px"
}
} */
'and/then/this.json',
/* Import from an JavaScript Object: */
{
environmentVariables: { '--branding-padding': '20px' }
},
/* Import from a JavaScript Function: */
() => {
const environmentVariables = { '--branding-padding': '20px' }
return { environmentVariables }
}
]
})
```
See example imports written in [JS](test/import-variables.js) and [JSON](test/import-variables.json).
Currently only valid [custom property names] (beginning with `--`) are accepted.
Not all valid [declaration value names] are accepted.
[cli-url]: https://github.com/csstools/postcss-env-function/actions/workflows/test.yml?query=workflow/test
[css-url]: https://cssdb.org/#environment-variables
[git-url]: https://gitter.im/postcss/postcss
[npm-url]: https://www.npmjs.com/package/postcss-env-function
[CSS Environment Variables]: https://drafts.csswg.org/css-env-1/
[PostCSS]: https://github.com/postcss/postcss
[PostCSS Environment Variables]: https://github.com/csstools/postcss-env-function
[custom property names]: https://drafts.csswg.org/css-variables-1/#typedef-custom-property-name
[declaration value names]: https://drafts.csswg.org/css-syntax-3/#typedef-declaration-value