I crated many mixins to generate different kinds of classes for various purposes. Specifically I have to use a unique colorizer set using the standard bootstrap variable name, such as (only an example):
#type-primary: #fff;
#type-success: #f00;
#type-info: #ff0;
#type-default: #000;
#type-warning: #0f0;
#type-danger: #0ff;
Actually I created my mixins in the following form, with a "mother" as prefix to which I attached various suffixes
.text
{
&-primary { .color_text(#type-primary); }
&-success { .color_text(#type-success); }
&-info { .color_text(#type-info); }
&-default { .color_text(#type-default); }
&-warning { .color_text(#type-warning); }
&-danger { .color_text(#type-danger); }
}
After this, I can then create the final called mixin such as (so simple because it's only an example)
.color_text (#color)
{
color:#color;
}
I woud like to automate and optimize .text mixin to avoid many repeated rows, I think with a for loop. How could be possible?
Final results should be (in this case)
.text-primary {
color: #fff;
}
.text-success {
color: #f00;
}
.text-info {
color: #ff0;
}
.text-default {
color: #000;
}
.text-warning {
color: #0f0;
}
.text-danger {
color: #0ff;
}
In PSEUDO-CODE something like this could be ideal
#type-primary: #fff;
#type-success: #f00;
#type-info: #ff0;
.createContextClass("classNamePrefix",{#type-primary,#type-success,#type-info},mixinToBeCalled);
// Another call could be
.createContextClass("otherClassNamePrefix",{#type-primary,#type-success},otherMixinToBeCalled);
where, in relation to my original code, classNamePrefix should be the name of first part of final CSS class, then is passed an array with all kind of suffix that I wish in final CSS code, and mixinToBeCalled is the mixin that creates all css rules for final .text-primary, .text-success, .text-info.
For the moment, following Seven-Phases-Max' suggestion, I improved his solution in the following way
Related
when defining a mixin multiple times in LESS, and later calling that mixin as follows
.background-color() {
background: red;
}
.background-color() {
background: yellow;
}
body {
.background-color;
}
the result will be a combined output from all the defined mixins
body {
background: red; // << output from mixin #1
background: yellow; // << output from mixin #2
}
while when you apply the same scenario in both Sass & Stylus ( using their own syntax of course ), when you call a mixin that is defined multiple times across your stylesheets, Only the last defined one will be executed ( it will override all previously defined mixins ) as follows.
result Sass and Stylus
body {
background: yellow; // << output from mixin #2
}
how can I override a mixin in LESS so that the output will be from the last defined mixin ?
You can not override them, alternatively use a variable to define the 'background-color'. For Less variables the last declared win.
Also read Pattern-matching
In Less all matching mixins are compiled in the source. You can use namespace to prevent name collisions, for instance:
#ns1 {
.background-color() {
background: red;
}
}
#ns2 {
.background-color() {
background: yellow;
}
}
than you can use:
body {
#ns2 > .background-color;
}
Double properties are also not removed to make some browser hacks possible, example:
#myElement {
width: 300px;
width: 500px\9;
}
To find a solution for your use case you should reformulate your question and explain why you have these same named mixins in the first place.
In Less, I can write:
.outer {
.inner {
color: red;
}
}
.test {
.outer .inner;
}
But when I write:
.outer {
&-inner {
color: red;
}
}
.test {
.outer-inner;
}
When I remove the .test, the .outer-inner output properly, but when I add it back, the compiler says
.outer-inner is undefined.
Is there anyway to re-use the styles of .outer-inner?
Calling a mixin whose selector is formed by concatenation is currently not possible with Less. However the same is possible for selectors formed at compilation time using interpolation (also referred to as dynamically formed selectors).
The below (interpolated/dynamically formed selector) would work fine.
#selector: .box;
#{selector}{
color: red;
.child{
color:blue;
}
}
.demo{
.box; /* will create both parent & child */
}
.container{
&.box{
background: black;
}
}
.demo2{
.container.box;
}
whereas, the following example will not work.
.container{
&-box{
color: blue;
}
}
.demo2{
.container-box; /* this will not work */
}
Currently, one work-around to the scenario in question is to create two separate Less files.
In the first file (test.less) add the below code and compile it into a CSS file.
.outer {
&-inner {
color: red;
}
}
In the second file, import the CSS created from the first file with the (less) directive and then call/re-use the mixin.
#import (less) "test.css";
.test {
.outer-inner;
}
Note: As mentioned in comments by seven-phases-max, this issue is similar to this item. However both these issues are not the same as extend will not work with both interpolated selector (dynamically formed) and concatenated selector.
Option 2: Another option would be to write a dummy mixin or a separate detached ruleset with common properties and make use of it like below.
#dummy: {color: red}; // detached ruleset
.outer{
&-inner{
#dummy();
}
}
.test{
#dummy();
}
or
.dummy() {color: blue}; // dummy mixin and would produce no extra selector in output as it has parentheses.
.outer{
&-inner{
.dummy;
}
}
.test{
.dummy;
}
LESS has mixins which make it easy to re-use properties from one class or ID ruleset in another. Is there a way to reference properties for an element (without class or ID) inside another ruleset? I'd like to do something like:
// Defined in a base .less file somewhere
a {
color: blue;
}
// Defined within a more specific file
.myClass a {
color: red;
}
// #myElement is used within .myClass, but I'd like to re-use the
// base styles.
#myElement a {
a();
}
You can use *:extend() pseudo-class for that:
#myElement a {
background: green;
&:extend(a);
}
See: Extend
I need to set a Less variable to match the website's active theme, ie, each theme has a different color.
I'd like to set #themeColor to the right color, based on the HTML's body CSS class that defines the theme.
For example:
body.themeBlue { #themeColor: blue; }
body.themeRed { #themeColor: red; }
This way I'd only need to use the #themeColor variable inside the other Less files.
Can anyone help?
According to this (http://www.lesscss.org/#-scope) it is possible to do something like that, but I can't make it work. what is going on here?
The LESS file cannot read the actual class applied to the html body element at run time (you would probably need to implement a javascript solution to do something like that).
If you just want to have all themed css ready for use based on the body class, the best way to implement this to have all the necessary theme based css in a mixin, then apply it under the theme classes. This reduces code duplication. For example:
LESS
//mixin with all css that depends on your color
.mainThemeDependentCss() {
#contrast: lighten(#themeColor, 20%);
h1 {color: #themeColor;}
p {background-color: #contrast;}
}
//use the mixin in the themes
body.themeBlue {
#themeColor: blue;
.mainThemeDependentCss();
}
body.themeRed {
#themeColor: red;
.mainThemeDependentCss();
}
CSS Output
body.themeBlue h1 {
color: #0000ff;
}
body.themeBlue p {
background-color: #6666ff;
}
body.themeRed h1 {
color: #ff0000;
}
body.themeRed p {
background-color: #ff6666;
}
For some other answers that deal with aspects or ways of theming, see:
LESS CSS - Change variable value for theme colors depending on body class
LESS.css variable depending on class
LESS CSS: abusing the & Operator when nesting?
Variables in Less are actually constants and will only be defined once.
Scope works within its code braces, so you would need to nest your CSS within each theme you want (which means duplication).
This is not ideal as you would need to do this:
body.themeBlue {
#color: blue;
/* your css here */
}
body.themeRed {
#color: red;
/* your css here AGAIN :( */
}
You could, however, try to use variables like this:
#color: black;
#colorRed: red;
#colorBlue: blue;
h1 {
color: #color; // black
body.themeRed & {
color: #colorRed; // red
}
body.themeBlue & {
color: #colorBlue; // blue
}
}
You would only need to declare the colours once, but you would need to constantly do the "body.themeRed" etc. prefixes where the colour varies depending on the theme.
You could actually use #import to load your theme! So common.less would contain all your default styles and #themeColor will be applied to it.
.mainThemeDependentCss() {
//file with all themed styles
#import 'common.less';
}
//use the mixin in the themes
body.themeBlue {
#themeColor: blue;
.mainThemeDependentCss();
}
body.themeRed {
#themeColor: red;
.mainThemeDependentCss();
}
BTW you should avoid using body selector in your common.less, because it wouldn't work.
I'm trying to use string interpolation on my variable to reference another variable:
// Set up variable and mixin
$foo-baz: 20px;
#mixin do-this($bar) {
width: $foo-#{$bar};
}
// Use mixin by passing 'baz' string as a param for use $foo-baz variable in the mixin
#include do-this('baz');
But when I do this, I get the following error:
Undefined variable: "$foo-".
Does Sass support PHP-style variable variables?
This is actually possible to do using SASS maps instead of variables. Here is a quick example:
Referencing dynamically:
$colors: (
blue: #007dc6,
blue-hover: #3da1e0
);
#mixin colorSet($colorName) {
color: map-get($colors, $colorName);
&:hover {
color: map-get($colors, #{$colorName}-hover);
}
}
a {
#include colorSet(blue);
}
Outputs as:
a { color:#007dc6 }
a:hover { color:#3da1e0 }
Creating dynamically:
#function addColorSet($colorName, $colorValue, $colorHoverValue: null) {
$colorHoverValue: if($colorHoverValue == null, darken( $colorValue, 10% ), $colorHoverValue);
$colors: map-merge($colors, (
$colorName: $colorValue,
#{$colorName}-hover: $colorHoverValue
));
#return $colors;
}
#each $color in blue, red {
#if not map-has-key($colors, $color) {
$colors: addColorSet($color, $color);
}
a {
&.#{$color} { #include colorSet($color); }
}
}
Outputs as:
a.blue { color: #007dc6; }
a.blue:hover { color: #3da1e0; }
a.red { color: red; }
a.red:hover { color: #cc0000; }
Sass does not allow variables to be created or accessed dynamically. However, you can use lists for similar behavior.
scss:
$list: 20px 30px 40px;
#mixin get-from-list($index) {
width: nth($list, $index);
}
$item-number: 2;
#smth {
#include get-from-list($item-number);
}
css generated:
#smth {
width: 30px;
}
http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html#lists
http://sass-lang.com/docs/yardoc/Sass/Script/Functions.html#list-functions
Anytime I need to use a conditional value, I lean on functions. Here's a simple example.
$foo: 2em;
$bar: 1.5em;
#function foo-or-bar($value) {
#if $value == "foo" {
#return $foo;
}
#else {
#return $bar;
}
}
#mixin do-this($thing) {
width: foo-or-bar($thing);
}
Here's another option if you're working with rails, and possibly under other circumstances.
If you add .erb to the end of the file extension, Rails will process erb on the file before sending it to the SASS interpreter. This gives you a can chance to do what you want in Ruby.
For example: (File: foo.css.scss.erb)
// Set up variable and mixin
$foo-baz: 20px; // variable
<%
def do_this(bar)
"width: $foo-#{bar};"
end
%>
#target {
<%= do_this('baz') %>
}
Results in the following scss:
// Set up variable and mixin
$foo-baz: 20px; // variable
#target {
width: $foo-baz;
}
Which, of coarse, results in the following css:
#target {
width: 20px;
}
I came across the need to reference a colour dynamically recently.
I have a _colours.scss file for every project, where I define all my colours once and reference them as variables throughout.
In my _forms.scss file I wanted to setup button styles for each colour available. Usually a tedious task. This helped me to avoid having to write the same code for each different colour.
The only downside is that you have to list each colour name and value prior to writing the actual css.
// $red, $blue - variables defined in _colours.scss
$colours:
'red' $red,
'blue' $blue;
#each $name, $colour in $colours {
.button.has-#{$name}-background-color:hover {
background-color: lighten($colour, 15%);
}
}
I needed to use dynamic color values in sass variables.
After lots of search, I applied this solution:
In application.html.erb:
<style>
:root {
--primary-color: <%= current_client.header_color %>;
--body-color: <%= current_client.footer_color %>;
}
</style>
In variables.sass:
$primary: var(--primary-color);
And boom you are good to go!
Reference: https://medium.com/angular-in-depth/build-truly-dynamic-theme-with-css-variables-539516e95837
To make a dynamic variable is not possible in SASS as of now, since you will be adding/connecting another var that needs to be parsed once when you run the sass command.
As soon as the command runs, it will throw an error for Invalid CSS, since all your declared variables will follow hoisting.
Once run, you can't declare variables again on the fly
To know that I have understood this, kindly state if the following is correct:
you want to declare variables where the next part (word) is dynamic
something like
$list: 100 200 300;
#each $n in $list {
$font-$n: normal $n 12px/1 Arial;
}
// should result in something like
$font-100: normal 100 12px/1 Arial;
$font-200: normal 200 12px/1 Arial;
$font-300: normal 300 12px/1 Arial;
// So that we can use it as follows when needed
.span {
font: $font-200;
p {
font: $font-100
}
}
If this is what you want, I am afraid as of now, this is not allowed