3.7 KiB
PostCSS Environment Variables
PostCSS Environment Variables lets you use env()
variables in CSS,
following the CSS Environment Variables specification.
@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:
npm install postcss-env-function --save-dev
Use PostCSS Environment Variables to process your CSS:
const postcssEnvFunction = require('postcss-env-function');
postcssEnvFunction.process(YOUR_CSS /*, processOptions, pluginOptions */);
Or use it as a PostCSS plugin:
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 | PostCSS CLI | Webpack | Create React App | Gulp | 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.
postcssCustomProperties({
importFrom: 'path/to/file.js' /* module.exports = {
environmentVariables: {
'--branding-padding': '20px',
'--branding-small': '600px'
}
} */
});
@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
variables-variables
key.
postcssCustomProperties({
importFrom: [
'path/to/file.js', // module.exports = { environmentVariables: { '--branding-padding': '20px' } }
'and/then/this.json', // { "environment-variables": { "--branding-padding": "20px" } }
{
environmentVariables: { '--branding-padding': '20px' }
},
() => {
const environmentVariables = { '--branding-padding': '20px' };
return { environmentVariables };
}
]
});