What is pixrem?
The pixrem npm package is a PostCSS plugin that converts pixel units to rem units in CSS. This is particularly useful for responsive web design, where rem units can provide more flexibility and scalability compared to fixed pixel units.
What are pixrem's main functionalities?
Convert px to rem
This feature converts pixel units to rem units in the provided CSS. The rootValue option specifies the root font size, which is used as the base for the conversion.
const postcss = require('postcss');
const pixrem = require('pixrem');
const css = 'body { font-size: 16px; }';
const options = { rootValue: 16 };
postcss([pixrem(options)])
.process(css)
.then(result => {
console.log(result.css);
});
Custom root value
This feature allows you to specify a custom root value for the conversion. In this example, the root value is set to 10, so 32px will be converted to 3.2rem.
const postcss = require('postcss');
const pixrem = require('pixrem');
const css = 'h1 { margin: 32px 0; }';
const options = { rootValue: 10 };
postcss([pixrem(options)])
.process(css)
.then(result => {
console.log(result.css);
});
Replace only specific properties
This feature allows you to replace only specific properties or at-rules. The options object can be configured to target specific CSS properties or at-rules for conversion.
const postcss = require('postcss');
const pixrem = require('pixrem');
const css = 'h1 { margin: 32px 0; padding: 16px; }';
const options = { rootValue: 16, replace: true, atrules: true, html: true, browsers: 'last 2 versions' };
postcss([pixrem(options)])
.process(css)
.then(result => {
console.log(result.css);
});
Other packages similar to pixrem
postcss-pxtorem
The postcss-pxtorem package is another PostCSS plugin that converts pixel units to rem units. It offers similar functionality to pixrem but includes additional options for controlling which properties are converted and supports media queries.
postcss-px-to-viewport
The postcss-px-to-viewport package converts pixel units to viewport units (vw, vh). While it serves a different purpose compared to pixrem, it is also used for responsive design by converting fixed units to scalable units based on the viewport size.
postcss-px-to-em
The postcss-px-to-em package converts pixel units to em units. Similar to pixrem, it helps in creating responsive designs by converting fixed units to relative units, but it uses em instead of rem.
Pixrem
PostCSS plugin that generates pixel fallbacks for rem units.
Installation
npm install --save pixrem
Usage
Pixrem is a CSS post-processor that, given CSS and a root em value, returns CSS with pixel unit fallbacks or replacements. It's based on browser data so only needed fallbacks will be added. Basically, it's for IE8 or less, and for IE9 & IE10 in the font
shorthand property and in pseudo-elements.
Example
'use strict';
var fs = require('fs');
var pixrem = require('pixrem');
var postcss = require('postcss');
var css = fs.readFileSync('main.css', 'utf8');
var processedCss = postcss([pixrem]).process(css).css;
fs.writeFile('main.with-fallbacks.css', processedCss, function (err) {
if (err) {
throw err;
}
console.log('IE8, you\'re welcome.');
});
Pixrem takes this:
.sky {
margin: 2.5rem 2px 3em 100%;
color: blue;
}
@media screen and (min-width: 20rem) {
.leaf {
margin-bottom: 1.333rem;
font-size: 1.5rem;
}
}
And returns this:
.sky {
margin: 80px 2px 3em 100%;
margin: 2.5rem 2px 3em 100%;
color: blue;
}
@media screen and (min-width: 20rem) {
.leaf {
margin-bottom: 1.333rem;
font-size: 1.5rem;
}
}
Options
Type: Object | Null
Default: {rootValue: 16, replace: false, atrules: false, html: true, browsers: 'ie <= 8', unitPrecision: 3}
rootValue
the root element font size. Can be px
, rem
, em
, %
, or unitless pixel value. Pixrem also tries to get the root font-size from CSS (html
or :root
) and overrides this option. Use html
option to disable this behaviour.replace
replaces rules containing rem
s instead of adding fallbacks.atrules
generates fallback in at-rules too (media-queries)html
overrides root font-size from CSS html {}
or :root {}
browsers
sets browser's range you want to target, based on browserslistunitPrecision
control the significant digits after the decimal point
Contribute
Report bugs and feature proposals in the Github issue tracker. Run tests with npm test
. In lieu of a formal styleguide, take care to maintain the existing coding style.
License
MIT