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