PostCSS from Sass
by mmyoji
2 min read
Motivation
I'd used Sass (.scss
) in a Nuxt.js project. But Nuxt.js doesn't support Sass
natively. Removing node-sass
and sass-loader
will make me easier to maintain
the project.
In addition, I have lately heard that PostCSS is modern CSS pre-/post-processor and you should use it. Nuxt.js also supports it w/o installing additional npm packages.
Then I switched from Sass to PostCSS.
What is changed?
A quantity of Sass in the project was not so large and it was not hard to migrate into PostCSS. There might be another difficulties for a larger Sass project, I would write what was required in the migration.
Variables
$primary-blue: #58c3e0;
.button {
background-color: $primary-blue;
}
to
:root {
--primary-blue: #58c3e0;
}
.button {
background-color: var(--primary-blue);
}
Single Line CSS
I'm not sure this might be happen always. At least a single line CSS didn't work in my project. (and unfortunately, there was no warning/error logs for it.)
/* doesn't work */
.foo {
color: red;
}
/* works */
.foo {
color: red;
}
Nesting
There're plugins for CSS nesting: postcss-nested and postcss-nesting.
If you use postcss-preset-env
(and I personally think you should use this normally) with stage: 3
, you can
use the latter postcss-nesting
. see:
https://github.com/csstools/postcss-preset-env#features
But if you want to use Sass-style nesting, use postcss-nested
and you don't
need to rewrite nested CSSs.
postcss-nesting
(and future CSS nesting) will be like this:
.foo {
color: red;
/* need `&` unlike Sass nesting */
& .hoge {
font-size: 12px;
}
}
/* becomes */
.foo {
color: red;
}
.foo .hoge {
font-size: 12px;
}
@for
There's postcss-for plugin.
However, because the utility CSS classes in my project were not often used, I
removed @for
and wrote some classes manually.
darken
color function
There's very useful color functions in Sass: darken
and lighten
. Luckily we
have a plugin
postcss-color-function, but
it requires a slight change for the former Sass functions.
.foo {
background-color: darken($primary-blue, 20%);
}
to
.foo {
background-color: color(var(--primary-blue), shade(20%));
}
This seems verbose and I gave up using this plugin. I prepare darker/lighter variables and use them directly.
Summary
There might be harder if your project has a lot of Sass features, but it's better choise to use PostCSS for future CSS development and it worths it.
You can add necessary plugins gradually when you need it in PostCSS development. Though we often write styles inside a component (like React and Vue.js) in modern web development, global styling sometimes might be necessary and PostCSS is one of the best choices for it.