How to extract common scss code from multiple files? - sass

After converting a lot of redundant crappy css files into scss files, I have a bunch of scss files. I'm pretty sure there is a lot of common css repeated among these files and I would like to extract this code.
As an example, let's say I have this block of scss code (let's call it block A) :
.test {
color: white;
.toto {
background: red;
font-size: 12px;
}
}
And another block (that we'll call block B) :
.test {
color: black;
.toto {
background: blue;
font-size: 12px;
text-align: center;
}
}
I want to be able to extract the following common scss code from block A and B :
.test {
.toto {
font-size: 12px;
}
}
It seems like a simple task to do, but with a large list of long scss files, it's really painful to do it manually. After searching for a while I didn't find any tool for that.
An intermediary solution could be to convert sass code to a multi-dimensionnal associative array and to process arrays to find intersections, but I could not find any simple solution to do that either, so any help would be appreciated.

There are a few approaches but in this instance, I would opt for a variable:
$base-font-size: 12px;
.test {
color: white;
.toto {
background: red;
font-size: $base-font-size;
}
}
.test {
color: black;
.toto {
background: blue;
font-size: $base-font-size;
text-align: center;
}
}
Or you could add a toto mixin with some defaults and use that:
#mixin toto($background: red, $text-align: left, $font-size: 12px) {
.toto {
background: $background;
text-align: $text-align;
font-size: $font-size;
}
}
.test {
color: white;
#include toto();
}
.test {
color: black;
#include toto(blue, center);
}
EDIT: or use extend:
.font-size-12 {
font-size: 12px;
}
.test {
color: white;
.toto {
#extend .font-size-12;
background: red;
}
}
.test {
color: black;
.toto {
#extend .font-size-12;
background: blue;
text-align: center;
}
}

Related

How to stop #mixin in SCSS from duplicating CSS?

I want to use one CSS style for two classes with mixin, but when I use mixin the final result will be 2 classes with the same CSS.
I have shared my code example below:
#mixin btnhover {
background-color: $bg-cl-blc;
color: $txt-cl-ff;
}
.btn-base {
font-size: 15px;
&:hover {
#include btnhover;
}
}
.btn-otln {
font-size: 15px;
&:hover {
#include btnhover;
}
}
**OUTPUT CSS**
.btn-base:hover {
background-color: #000;
color: #fff;
}
.btn-otln:hover {
background-color: #000;
color: #fff;
}
This is how Sass works - it allows for better organisation of the code, but this code is then compiled, retaining functionality and not caring about other aspects.
If you really care about how the output code is structured, I would suggest to create a separate style for the classes with the hover effect:
#mixin btnhover {
background-color: #000;
color: #fff;
}
.btn-base {
font-size: 15px;
}
.btn-otln {
font-size: 15px;
}
.btn-base:hover,
.btn-otln:hover {
#include btnhover;
}
But in this approach, the use of mixin (and Sass) is questionable (in this exact case).
Generally, when you use Sass (or any other compiled language), you don't really care about the output CSS.
This won't be your answer, but I want to show you another way to make a mixin
#mixin btnhover($back, $color) {
background: $back;
color: $color;
}
When you use it, you can plug in the values
#include mixin btnhover($bg-cl-blc, $txt-cl-ff)
That way you can use the mixin over and over in different places with different values
Just discovered this recently myself, it's a concept called 'placeholders' in SASS syntax (see example below). I've done my best to apply it to your situation below....
Put this in your .scss file:
$bg-cl-blc: #ff211a;
$txt-cl-ff: #fff;
$btn-base-size: 15px;
%btnhover {
background-color: $bg-cl-blc;
color: $txt-cl-ff;
}
%btn-common {
font-size: $btn-base-size;
}
.btn-base {
#extend %btn-common;
&:hover {
#extend %btnhover;
}
}
.btn-otln {
#extend %btn-common;
&:hover {
#extend %btnhover;
}
}
CSS output will look like this
.btn-otln:hover, .btn-base:hover {
background-color: #ff211a;
color: #fff;
}
.btn-otln, .btn-base {
font-size: 15px;
}
Great article written up on this here:
https://dev.to/kemotiadev/are-sass-mixins-really-that-lightweight-and-what-are-placeholders-119i

Prevent combination of multiple selectors

I'm trying to group all my vendor-specific stuff into a placeholder selector like this:
%search-bar-placeholder {
color: red;
}
.search-bar::-webkit-input-placeholder {
#extend %search-bar-placeholder;
}
.search-bar:-moz-placeholder {
#extend %search-bar-placeholder;
}
.search-bar::-moz-placeholder {
#extend %search-bar-placeholder;
}
.search-bar:-ms-input-placeholder {
#extend %search-bar-placeholder;
}
And then it compiles to this:
.search-bar::-webkit-input-placeholder, .search-bar:-moz-placeholder, .search-bar::-moz-placeholder, .search-bar:-ms-input-placeholder {
color: red; }
How can I make sure Sass doesn't put all the selectors together ? Like this:
.search-bar::-webkit-input-placeholder {
color: red;
}
.search-bar:-moz-placeholder {
color: red;
}
.search-bar::-moz-placeholder {
color: red;
}
.search-bar:-ms-input-placeholder {
color: red;
}
When looking at Extend/Inheritance at sass-lang.com it seems that the selectors will always be comma separated. Even if you add another property, it will keep the shared properties in the comma separated list, and add another selector just for that overridden value.
The way I achieved what you want is by using a mixin. Though it's not really the purpose of a mixin, it does get the job done. Your style is still centralized and you can print it out in each selector using a one liner too.
#mixin placeholder-properties() {
color: red;
font-weight: bold;
}
.search-bar::-webkit-input-placeholder {
#include placeholder-properties();
}
.search-bar:-moz-placeholder {
#include placeholder-properties();
}
.search-bar::-moz-placeholder {
#include placeholder-properties();
}
.search-bar:-ms-input-placeholder {
#include placeholder-properties();
}
The result will the following.
.search-bar::-webkit-input-placeholder {
color: red;
font-weight: bold;
}
.search-bar:-moz-placeholder {
color: red;
font-weight: bold;
}
.search-bar::-moz-placeholder {
color: red;
font-weight: bold;
}
.search-bar:-ms-input-placeholder {
color: red;
font-weight: bold;
}
Here's a fiddle.

how to inheritance multiples class through sass

I have a scenario in sass
.A{
background-color: red;
Padding :20px;
h4{ padding-bottom :20px;}
}
// another class
.B{
background-color : blue;
padding : 20px
h4{ padding-bottom:20px}
}
Question: how can i combine padding and h4 together in SASS without to repeating padding and h4 properties
The most straight forward way is to use #extend.
%common_properties {
padding: 20px;
h4 {
padding-bottom: 20px;
}
}
.a {
#extend %common_properties;
background-color: red;
}
.b {
#extend %common_properties;
background-color: blue;
}
You really don't save much by using sass/scss for this small of a redundancy
A solution with scss:
.a, .b {
padding: 20px;
background-color: red;
& h4 {
padding-bottom: 20px;
}
}
.b{
background-color:blue;
}
That solution in plain css:
.a, .b {
padding: 20px;
background-color: red;
}
.a h4, .b h4 {
padding-bottom: 20px;
}
.b {
background-color: blue;
}
Here is what that will look like:
http://codepen.io/cawoelk/pen/Ciqyw

Sass / Scss: Changing the order of nested psuedo selectors for :before and :hover in generated CSS?

Given the following Sass:
div.test {
display: inline-block;
background-color: #ffffff;
color: #000000;
&:before {
& {
&:hover {
border: 1px solid salmon;
}
}
width: 25px;
height: 25px;
content: "";
}
}
The resulting CSS compiles to:
div.test {
display: inline-block;
background-color: #ffffff;
color: #000000;
}
div.test:before {
width: 25px;
height: 25px;
content: "";
}
div.test:before:hover {
border: 1px solid salmon;
}
What I am attempting to do is generate div.test:hover:before (the current output is before:hover).
NOTE: I am able to generate the expected CSS by using the following Sass:
div.test {
display: inline-block;
background-color: #ffffff;
color: #000000;
&:hover {
&:before {
border: 1px solid salmon;
}
}
&:before {
width: 25px;
height: 25px;
content: "";
}
}
However I would like to know if it is possible using the first nested approach or some modification of it.
The goal was to avoid having to repeat &:before if there was such a way to do so using Sass syntax. I am also OK with knowing it isn't possible.
While initially the plan was to have '&' available in SassScript as a string that could be manipulated so that you could insert values wherever you wanted, those plans have been abandoned for 3.3 due to complication. Unfortunately you'll have to wait a while to be able to do this. At the moment '&' is immutable and just means "whatever the selector chain up to this point is".
EDIT (2020.02.15):
it is now technically possible to achieve this with recent versions of dart-sass:
#use "sass:selector";
#mixin unify-parent($child) {
#at-root #{selector.unify(&, $child)} {
#content;
}
}
div.test {
display: inline-block;
background-color: #ffffff;
color: #000000;
&:before {
width: 25px;
height: 25px;
content: "";
#include unify-parent(":hover") {
border: 1px solid salmon;
}
}
}
Sources:
https://sass-lang.com/blog/the-module-system-is-launched
https://sass-lang.com/documentation/style-rules/parent-selector#advanced-nesting

Something between #include and #extend with sass

Is it possible to include a css rule in sass without duplicate the code?
With extend we are extending the code, but i dont want that eiter. I want include it, without duplicating code.
For example
SCSS:
.heading {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
h1 {
#extend .heading;
color: white;
}
}
.my-other-box {
.heading {
color: black;
}
}
HTML
<div class="box">
<h1>My heading</h1>
</div>
<div class="my-other-box">
<h1 class="heading">My heading</h1>
</div>
CSS
.heading, .box h1 {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
}
.box h1 {
color: white;
}
.my-other-box .heading,
.my-other-box .box h1,
.box .my-other-box h1 {
color: black;
}
So the two last rules there are because its extending (I understand the benifits of it).
But if i want to both use classes, and extends i dont want it to extend, just include it. But i dont want it to duplicate the code.
I want:
CSS
.heading, .box h1 {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
}
.box h1 {
color: white;
}
.my-other-box .heading {
color: black;
}
If you use an extend class (or use a class name that differs from one you're repeating elsewhere), you can get the output you're looking for:
%heading, .heading {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
h1 {
#extend %heading;
color: white;
}
}
.my-other-box {
.heading {
color: black;
}
}
Output:
.box h1, .heading {
font-size: 16px;
font-family: my-cool-font;
}
.box {
background: red;
}
.box h1 {
color: white;
}
.my-other-box .heading {
color: black;
}

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