Is there a way to prepend a selector directly to the current selector in scss. Consider the following:
.object-fit {
object-fit: cover;
height: 100%;
width: 100%;
overflow: hidden;
}
is there a way to prepend img so that the output is img.object-fit?
The only way I have seen for prepending is to add & after like so:
.object-fit {
img & {
}
}
but this would turn it into a parent child selector: img .object-fit
The normal way would be just to append the second selector with &img but as this has no dot before the selector, that ends up with a different class name: .object-fitimg
So basically the question is is there anyway inside the object fit class to prepend a bare element selector?
If you use #at-root and & with interpolation syntax:
.object-fit {
#at-root img#{&} {
color: blue;
}
}
Your output will be:
img.object-fit{
color: blue;
}
Complete answer here is #at-root selector-append(), which will also work for multiple parent selectors.
Source: https://github.com/sass/sass/issues/2059#issuecomment-218862922
.object-fit,
.non-fit {
#at-root #{selector-append("img", &)} {
color: blue;
}
}
Output
img.object-fit, img.non-fit {
color: blue;
}
Related
I inherited some CSS code, which is making use of the & character prior to the id name to style it. It looks something like this:
&#my-id {
// Content and attributes
}
There are also other instances of it, such as:
&:before {
// content and attributes
}
and
&:hover {
// content and attributes
}
What do those mean? I can't find a good way to express this in a search, so I can't find anything. My apologies if this is a duplicate.
It refers to the parent selector.
Input:
.parent {
&.child {
color: red;
}
}
Output:
.parent.child { color: red }
It's really helpful if you're writing CSS in BEM format, something like:
.block {
&__element {
width: 100px;
height: 100px;
&--modifier {
width: 200px;
}
}
}
.block__element { width: 100px; height: 100px;}
.block__element--modifier { width: 200px;}
<div class="block__element"></div>
<div class="block__element block__element--modifier"></div>
And finally, all examples I've shared have been concatenating the class names, but you can also use it as a reference, like:
.parent {
& .child {
color: red;
}
}
.parent {
.child & {
color: blue;
}
}
.parent .child { color: red }
.child .parent { color: blue }
Additional references:
http://lesscss.org/features/#parent-selectors-feature
https://blog.slaks.net/2013-09-29/less-css-secrets-of-the-ampersand/
Using the ampersand (SASS parent selector) inside nested selectors
It's a built-in feature of Sass: https://css-tricks.com/the-sass-ampersand/
You can use it when you're nesting selectors and you need a more specific selector, like an element that has both of two classes:
If your CSS looks like this:
.some-class.another-class { }
And you wanted to nest, the Sass equivalent is:
.some-class {
&.another-class {}
}
In the following code example I generate two squares that ideally should turn red.
The first div .with-root currently stays blue, the second div .without-root turns red. I expect this behaviour, but don't see a proper solution to turn the .with-root div red as well.
Note the difference in the scss file: the first div works with a fixed parent selector, the second one doesn't have a parent. For CSS specificity I need to work with the .with-root {} wrapper.
.with-root {
.with-root__element {
display: block;
width: 5rem;
height: 5rem;
background: blue;
&--red & {
&__item {
background: red;
}
}
}
}
.without-root {
&__element {
display: block;
width: 5rem;
height: 5rem;
background: blue;
&--red & {
&__item {
display: block;
width: 5rem;
height: 5rem;
background: red;
}
}
}
}
The codepen can be found here: https://codepen.io/studiotwist/pen/OzMOmr
Well now that I hopefully understood your question I deleted my wrong idea before and the following solution should work.
Maybe there could be a logic erorr. You have actually three class definitions of .with-root__element and two of them are extended with --red and __item, but the 3rd one is however an extra class which comes in conflict with the other two. You're basically concatenating the endings --red and __item with the parent selector *__element. Also, the --red class is nested inside the *__element one without ending in your CSS but in HTML it is not. *__element and *__element--red are attached in the same HTML tag.
DEBUG
Only showing the first DIV.
.with-root {
.with-root__element {
display: block;
width: 5rem;
height: 5rem;
background: blue;
&--red {
//#error &; // this reference contains the entire document root including the root element .with-root which is wrong
#{&} &__item {
//#error #{&} &__item; // this is a wrong concatenation plus it takes the entire root with it
background: red; // thus, this won't render
}
}
}
}
Debug in action # Sassmeister
POSSIBLE FIX
#mixin bg($bg) {
width: 5rem;
height: 5rem;
background: $bg;
}
.with-root__element {
#include bg(blue);
$this: &;
#at-root {
.with-root {
#{$this}--red #{$this}__item {
#include bg(red);
}
}
}
}
.without-root {
&__element {
#include bg(blue);
&--red &__item {
#include bg(red);
}
}
}
Fork
#at-root is a directive which is useful for your issue as it basically crops the nesting level of the selector and styles can be defined inside the root-body by referencing the parent selector instead of the entire root. So I added a variable $this which will cache the reference. display: block is not needed as div elements have it by default. Sorry about the mixin, it's a habit. --red and __item have now the refence selector *__element.
#at-root Documentation
I have a code that I can't change:
item.left,
item.centre,
item.right{
.MIXIN();
}
.MIXIN(){
width: 100px;
}
I need to apply width only to .right element. I can only change contents of MIXIN(). I was thinking of using &but it will result either in .right item.right or item.right .right which is not what I want. Is there a way to apply styling only for .right element using contents of MIXIN()?
You can use the negation CSS pseudo-class :not().
item.left,
item.centre,
item.right{
width: 20px;
&:not(.left):not(.centre) {
width: 100px;
}
}
Fiddle: https://jsfiddle.net/e0nd7pk4
You can not do it. The only way is to override the first declaration.
item.left,
item.centre {
width: inherit;
}
How about & but without the space:
.MIXIN() {
width: 100px;
&.right { color: red; }
}
It compiles down to item.right.right which is a bit weird but won't match left and center.
Fiddle: http://jsfiddle.net/c0634wg2/
I have a chunk of CSS that I want to "scope" to a specific block of HTML. I'm generating a unique ID and then setting it on the block of HTML and then would like to wrap the chunk of CSS with the same ID so that those selectors can't match sibling or parent elements. I don't know the contents of the chunk of CSS. Given a chunk of CSS:
.container {
background-color: black;
}
.container .title {
color: white;
}
.container .description {
color: grey;
}
I need it to come out like this:
.theme0 .container, .theme0.container {
background-color: black;
}
.theme0 .container .title, .theme0.container .title {
color: white;
}
.theme0 .container .description, .theme0.container .description {
color: grey;
}
Is there any way to do this with LESS? The first selector is easy, just wrap the CSS chunk with '.theme0 {' + cssChunk + '}'. But I haven't been able to figure out a way to prepend '.theme0' to all of the selectors without the space.
EDIT:
So I should clarify that our intentions are to build such a system into our build process / dependency system. We're attempting to scope a chunk of css to a react component. We have a couple different approaches we're trying out, this is just one of them. Point is, the CSS and HTML we're trying to scope could be anything, we have no control or knowledge of it. The first pattern can easily be achieved by prepending .uniqueID { and appending }. This gives .uniqueID .someSelector {}. I'm wondering if it's possible to do a similar thing but get .uniqueID.someSelector {}? Ideally without having to write the original chunk of CSS with knowledge of our scoping system.
Assuming the component styles are in a separate CSS file, i.e.:
// component.css
.container {
background-color: black;
}
.container .title {
color: white;
}
.container .description {
color: grey;
}
The wrapper code could be:
.theme0 {
#import (less) "component.css";
&.container:extend(.theme0 .container all) {}
}
in less you can nest selectors for selecting inside that element like:
.theme {
color: black;
.container {
color: blue;
}
}
This wil generate:
.theme {
color:black;
}
.theme .container {
color:blue;
}
Creating elements that are connected is easy enof:
.test#badge will select a class test width an id badge
In less this is dont with the & symbol. (this selects the starting property)
.test {
color: blue;
&#badge {
color:black;
}
}
Compiles to:
.test {
color: blue;
}
.test#badge {
color: black;
}
And for the final selector:
To get the output of .test, .container use the function: .test:extends(.container);
.test {
color: black;
&:extends(.conatiner);
}
.container {
color: pink;
}
Compiles to:
.test {
color: black;
}
.test, .container {
color: pink;
}
You can even extend multiple ones in a single line:
.test:extends(.oclas, .tclss);
and its wil work as abose only for both classes. So outputed selectors would be .test, .oclass and .test, .tclass
I want to add scope to my selectors.
A good way to achieve it in my opinion is to select css selector and return mySelector + oldSelector
For example I have .old { background: black; }, I would transform it into .mySelector .old { background: black; }
Let's say I have this CSS
.a
{
background: red;
}
#b {
background: green;
}
input {
background: blue;
}
[type=custom] {
background: white;
}
I would do .+?{, but it selects not needed parts. Inverse of {.+?} would work, but I don't know how to inverse it. Any ideas ?
I figured out I can use String.match({.+?}) to get all rules and String.split({.+?}) to get selectors in JavaScript.
Also I've found a library to easily parse CSS in JavaScript https://github.com/reworkcss/css