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