sass-site/source/documentation/style-rules/parent-selector.html.md.erb
2019-03-04 16:24:31 -08:00

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---
title: Parent Selector
introduction: >
The parent selector, `&`, is a special selector invented by Sass thats used
in [nested selectors](../style-rules#nesting) to refer to the outer selector.
It makes it possible to re-use the outer selector in more complex ways, like
adding a
[pseudo-class](https://developer.mozilla.org/en-US/docs/Web/CSS/Pseudo-classes)
or adding a selector *before* the parent.
---
When a parent selector is used in an inner selector, it's replaced with the
corresponding outer selector. This happens instead of the normal nesting
behavior.
<% example do %>
.alert {
// The parent selector can be used to add pseudo-classes to the outer
// selector.
&:hover {
font-weight: bold;
}
// It can also be used to style the outer selector in a certain context, such
// as a body set to use a right-to-left language.
[dir=rtl] & {
margin-left: 0;
margin-right: 10px;
}
// You can even use it as an argument to pseudo-class selectors.
:not(&) {
opacity: 0.8;
}
}
===
.alert
// The parent selector can be used to add pseudo-classes to the outer
// selector.
&:hover
font-weight: bold
// It can also be used to style the outer selector in a certain context, such
// as a body set to use a right-to-left language.
[dir=rtl] &
margin-left: 0
margin-right: 10px
// You can even use it as an argument to pseudo-class selectors.
:not(&)
opacity: 0.8
<% end %>
<% heads_up do %>
Because the parent selector could be replaced by a type selector like `h1`,
it's only allowed at the beginning of compound selectors where a type selector
would also be allowed. For example, `span&` is not allowed.
We're looking into loosening this restriction, though. If you'd like to help
make that happen, check out [this GitHub issue][].
[this GitHub issue]: https://github.com/sass/sass/issues/1425
<% end %>
## Adding Suffixes
You can also use the parent selector to add extra suffixes to the outer
selector. This is particularly useful when using a methodology like [BEM][] that
uses highly structured class names. As long as the outer selector ends with an
alphanumeric name (like class, ID, and element selectors), you can use the
parent selector to append additional text.
[BEM]: http://getbem.com/
<% example do %>
.accordion {
max-width: 600px;
margin: 4rem auto;
width: 90%;
font-family: "Raleway", sans-serif;
background: #f4f4f4;
&__copy {
display: none;
padding: 1rem 1.5rem 2rem 1.5rem;
color: gray;
line-height: 1.6;
font-size: 14px;
font-weight: 500;
&--open {
display: block;
}
}
}
===
.accordion
max-width: 600px
margin: 4rem auto
width: 90%
font-family: "Raleway", sans-serif
background: #f4f4f4
&__copy
display: none
padding: 1rem 1.5rem 2rem 1.5rem
color: gray
line-height: 1.6
font-size: 14px
font-weight: 500
&--open
display: block
<% end %>
## In SassScript
The parent selector can also be used within SassScript. It's a special
expression that returns the current parent selector in the same format used
by [selector functions][]: a comma-separated list (the selector list) that
contains space-separated lists (the complex selectors) that contain unquoted
strings (the compound selectors).
<% example do %>
.main aside:hover,
.sidebar p {
parent-selector: &;
// => ((unquote(".main") unquote("aside:hover")),
// (unquote(".sidebar") unquote("p")))
}
===
.main aside:hover,
.sidebar p
parent-selector: &
// => ((unquote(".main") unquote("aside:hover")),
// (unquote(".sidebar") unquote("p")))
<% end %>
[selector functions]: ../functions/selector#selector-values
If the `&` expression is used outside any style rules, it returns `null`. Since
`null` is [falsey][], this means you can easily use it to determine whether a
mixin is being called in a style rule or not.
[falsey]: ../at-rules/control/if#truthiness-and-falsiness
<%= partial 'code-snippets/example-if-parent-selector' %>
### Advanced Nesting
You can use `&` as a normal SassScript expression, which means you can pass it
to functions or include it in interpolation—even in other selectors! Using it in
combination with [selector functions][] and the [`@at-root` rule][] allows you
to nest selectors in very powerful ways.
[`@at-root` rule]: ../at-rules/at-root
<%= partial 'code-snippets/example-advanced-nesting' %>
<% heads_up do %>
When Sass is nesting selectors, it doesn't know what interpolation was used to
generate them. This means it will automatically add the outer selector to the
inner selector *even if* you used `&` as a SassScript expression. That's why
you need to explicitly use the [`@at-root` rule][] to tell Sass not to include
the outer selector.
[`@at-root` rule]: ../at-rules/at-root
<% end %>