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74 lines
1.8 KiB
Plaintext
74 lines
1.8 KiB
Plaintext
---
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title: "null"
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introduction: >
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The value `null` is the only value of its type. It represents the absence of a
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value, and is often returned by [functions](../at-rules/function) to indicate
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the lack of a result.
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---
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<% example(autogen_css: false) do %>
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@use "sass:map";
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@use "sass:string";
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@debug string.index("Helvetica Neue", "Roboto"); // null
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@debug map.get(("large": 20px), "small"); // null
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@debug &; // null
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===
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@use "sass:map";
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@use "sass:string";
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@debug string.index("Helvetica Neue", "Roboto") // null
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@debug map.get(("large": 20px), "small") // null
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@debug & // null
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<% end %>
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If a [list][] contains a `null`, that `null` is omitted from the generated CSS.
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[list]: lists
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<% example do %>
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$fonts: ("serif": "Helvetica Neue", "monospace": "Consolas");
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h3 {
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font: 18px bold map-get($fonts, "sans");
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}
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===
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$fonts: ("serif": "Helvetica Neue", "monospace": "Consolas")
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h3
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font: 18px bold map-get($fonts, "sans")
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<% end %>
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If a property value is `null`, that property is omitted entirely.
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<% example do %>
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$fonts: ("serif": "Helvetica Neue", "monospace": "Consolas");
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h3 {
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font: {
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size: 18px;
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weight: bold;
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family: map-get($fonts, "sans");
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}
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}
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===
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$fonts: ("serif": "Helvetica Neue", "monospace": "Consolas")
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h3
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font:
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size: 18px
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weight: bold
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family: map-get($fonts, "sans")
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<% end %>
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`null` is also [*falsey*][], which means it counts as `false` for any rules or
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[operators][] that take booleans. This makes it easy to use values that can be
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`null` as conditions for [`@if`][] and [`if()`][].
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[*falsey*]: ../at-rules/control/if#truthiness-and-falsiness
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[operators]: ../operators/boolean
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[`@if`]: ../at-rules/control/if
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[`if()`]: ../modules#if
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<%= partial 'code-snippets/example-if-parent-selector' %>
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