sass-site/old_source/documentation/modules/selector.html.md.erb
2023-01-06 17:37:45 -05:00

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---
title: sass:selector
---
<%= partial '../snippets/built-in-module-status' %>
## Selector Values
The functions in this module inspect and manipulate selectors. Whenever they
return a selector, it's always a comma-separated [list][] (the selector list)
that contains space-separated lists (the complex selectors) that contain
[unquoted strings][] (the compound selectors). For example, the selector `.main
aside:hover, .sidebar p` would be returned as:
[list]: ../values/lists
[unquoted strings]: ../values/strings#unquoted
```scss
@debug ((unquote(".main") unquote("aside:hover")),
(unquote(".sidebar") unquote("p")));
// .main aside:hover, .sidebar p
```
Selector arguments to these functions may be in the same format, but they can
also just be normal strings (quoted or unquoted), or a combination. For example,
`".main aside:hover, .sidebar p"` is a valid selector argument.
<% function 'selector.is-superselector($super, $sub)',
'is-superselector($super, $sub)',
returns: 'boolean' do %>
Returns whether the selector `$super` matches all the elements that the
selector `$sub` matches.
Still returns true even if `$super` matches *more* elements than `$sub`.
The `$super` and `$sub` selectors may contain [placeholder selectors][], but
not [parent selectors][].
[placeholder selectors]: ../style-rules/placeholder-selectors
[parent selectors]: ../style-rules/parent-selector
<% example(autogen_css: false) do %>
@debug selector.is-superselector("a", "a.disabled"); // true
@debug selector.is-superselector("a.disabled", "a"); // false
@debug selector.is-superselector("a", "sidebar a"); // true
@debug selector.is-superselector("sidebar a", "a"); // false
@debug selector.is-superselector("a", "a"); // true
===
@debug selector.is-superselector("a", "a.disabled") // true
@debug selector.is-superselector("a.disabled", "a") // false
@debug selector.is-superselector("a", "sidebar a") // true
@debug selector.is-superselector("sidebar a", "a") // false
@debug selector.is-superselector("a", "a") // true
<% end %>
<% end %>
<% function 'selector.append($selectors...)',
'selector-append($selectors...)',
returns: 'selector' do %>
Combines `$selectors` without [descendant combinators][]—that is, without
whitespace between them.
[descendant combinators]: https://developer.mozilla.org/en-US/docs/Web/CSS/Descendant_selectors
If any selector in `$selectors` is a selector list, each complex selector is
combined separately.
The `$selectors` may contain [placeholder selectors][], but not [parent
selectors][].
[placeholder selectors]: ../style-rules/placeholder-selectors
[parent selectors]: ../style-rules/parent-selector
See also [`selector.nest()`](#nest).
<% example(autogen_css: false) do %>
@debug selector.append("a", ".disabled"); // a.disabled
@debug selector.append(".accordion", "__copy"); // .accordion__copy
@debug selector.append(".accordion", "__copy, __image");
// .accordion__copy, .accordion__image
===
@debug selector.append("a", ".disabled") // a.disabled
@debug selector.append(".accordion", "__copy") // .accordion__copy
@debug selector.append(".accordion", "__copy, __image")
// .accordion__copy, .accordion__image
<% end %>
<% end %>
<% function 'selector.extend($selector, $extendee, $extender)',
'selector-extend($selector, $extendee, $extender)',
returns: 'selector' do %>
Extends `$selector` as with the [`@extend` rule][].
[`@extend` rule]: ../at-rules/extend
Returns a copy of `$selector` modified with the following `@extend` rule:
```scss
#{$extender} {
@extend #{$extendee};
}
```
In other words, replaces all instances of `$extendee` in `$selector` with
`$extendee, $extender`. If `$selector` doesn't contain `$extendee`, returns it
as-is.
The `$selector`, `$extendee`, and `$extender` selectors may contain
[placeholder selectors][], but not [parent selectors][].
[placeholder selectors]: ../style-rules/placeholder-selectors
[parent selectors]: ../style-rules/parent-selector
See also [`selector.replace()`](#replace).
<% example(autogen_css: false) do %>
@debug selector.extend("a.disabled", "a", ".link"); // a.disabled, .link.disabled
@debug selector.extend("a.disabled", "h1", "h2"); // a.disabled
@debug selector.extend(".guide .info", ".info", ".content nav.sidebar");
// .guide .info, .guide .content nav.sidebar, .content .guide nav.sidebar
===
@debug selector.extend("a.disabled", "a", ".link") // a.disabled, .link.disabled
@debug selector.extend("a.disabled", "h1", "h2") // a.disabled
@debug selector.extend(".guide .info", ".info", ".content nav.sidebar")
// .guide .info, .guide .content nav.sidebar, .content .guide nav.sidebar
<% end %>
<% end %>
<% function 'selector.nest($selectors...)',
'selector-nest($selectors...)',
returns: 'selector' do %>
Combines `$selectors` as though they were nested within one another in the
stylesheet.
The `$selectors` may contain [placeholder selectors][]. Unlike other selector
functions, all of them except the first may also contain [parent selectors][].
[placeholder selectors]: ../style-rules/placeholder-selectors
[parent selectors]: ../style-rules/parent-selector
See also [`selector.append()`](#append).
<% example(autogen_css: false) do %>
@debug selector.nest("ul", "li"); // ul li
@debug selector.nest(".alert, .warning", "p"); // .alert p, .warning p
@debug selector.nest(".alert", "&:hover"); // .alert:hover
@debug selector.nest(".accordion", "&__copy"); // .accordion__copy
===
@debug selector.nest("ul", "li") // ul li
@debug selector.nest(".alert, .warning", "p") // .alert p, .warning p
@debug selector.nest(".alert", "&:hover") // .alert:hover
@debug selector.nest(".accordion", "&__copy") // .accordion__copy
<% end %>
<% end %>
<% function 'selector.parse($selector)',
'selector-parse($selector)',
returns: 'selector' do %>
Returns `$selector` in the [selector value](#selector-values) format.
<% example(autogen_css: false) do %>
@debug selector.parse(".main aside:hover, .sidebar p");
// ((unquote(".main") unquote("aside:hover")),
// (unquote(".sidebar") unquote("p")))
===
@debug selector.parse(".main aside:hover, .sidebar p")
// ((unquote(".main") unquote("aside:hover")),
// (unquote(".sidebar") unquote("p")))
<% end %>
<% end %>
<% function 'selector.replace($selector, $original, $replacement)',
'selector-replace($selector, $original, $replacement)',
returns: 'selector' do %>
Returns a copy of `$selector` with all instances of `$original` replaced by
`$replacement`.
This uses the [`@extend` rule][]'s [intelligent unification][] to make sure
`$replacement` is seamlessly integrated into `$selector`. If `$selector`
doesn't contain `$original`, returns it as-is.
[`@extend` rule]: ../at-rules/extend
[intelligent unification]: ../at-rules/extend#how-it-works
The `$selector`, `$original`, and `$replacement` selectors may contain
[placeholder selectors][], but not [parent selectors][].
[placeholder selectors]: ../style-rules/placeholder-selectors
[parent selectors]: ../style-rules/parent-selector
See also [`selector.extend()`](#extend).
<% example(autogen_css: false) do %>
@debug selector.replace("a.disabled", "a", ".link"); // .link.disabled
@debug selector.replace("a.disabled", "h1", "h2"); // a.disabled
@debug selector.replace(".guide .info", ".info", ".content nav.sidebar");
// .guide .content nav.sidebar, .content .guide nav.sidebar
===
@debug selector.replace("a.disabled", "a", ".link") // .link.disabled
@debug selector.replace("a.disabled", "h1", "h2") // a.disabled
@debug selector.replace(".guide .info", ".info", ".content nav.sidebar")
// .guide .content nav.sidebar, .content .guide nav.sidebar
<% end %>
<% end %>
<% function 'selector.unify($selector1, $selector2)',
'selector-unify($selector1, $selector2)',
returns: 'selector | null' do %>
Returns a selector that matches only elements matched by *both* `$selector1`
and `$selector2`.
Returns `null` if `$selector1` and `$selector2` don't match any of the same
elements, or if there's no selector that can express their overlap.
Like selectors generated by the [`@extend` rule][], the returned selector
isn't guaranteed to match *all* the elements matched by both `$selector1` and
`$selector2` if they're both complex selectors.
[`@extend` rule]: ../at-rules/extend#html-heuristics
<% example(autogen_css: false) do %>
@debug selector.unify("a", ".disabled"); // a.disabled
@debug selector.unify("a.disabled", "a.outgoing"); // a.disabled.outgoing
@debug selector.unify("a", "h1"); // null
@debug selector.unify(".warning a", "main a"); // .warning main a, main .warning a
===
@debug selector.unify("a", ".disabled") // a.disabled
@debug selector.unify("a.disabled", "a.outgoing") // a.disabled.outgoing
@debug selector.unify("a", "h1") // null
@debug selector.unify(".warning a", "main a") // .warning main a, main .warning a
<% end %>
<% end %>
<% function 'selector.simple-selectors($selector)',
'simple-selectors($selector)',
returns: 'list' do %>
Returns a list of simple selectors in `$selector`.
The `$selector` must be a single string that contains a compound selector.
This means it may not contain combinators (including spaces) or commas.
The returned list is comma-separated, and the simple selectors are unquoted
strings.
<% example(autogen_css: false) do %>
@debug selector.simple-selectors("a.disabled"); // a, .disabled
@debug selector.simple-selectors("main.blog:after"); // main, .blog, :after
===
@debug selector.simple-selectors("a.disabled") // a, .disabled
@debug selector.simple-selectors("main.blog:after") // main, .blog, :after
<% end %>
<% end %>