unitless($number) Returns whether a number has units.

Pattern: :focus   Definition: The :focus pseudo-class

rgba($red, $green, $blue, $alpha) rgba($color, $alpha)

green($color) Gets the green component of a color. Calculated from HSL where necessary via

map_has_key($map, $key) Returns whether a map has a value associated with a given key.

type_of($value) Returns the type of a value.

mixin_exists($name) Check whether a mixin with the given name exists.

map_merge($map1, $map2) Merges two maps together into a new map. Keys in $map2 will take precedence over keys

Variable Defaults: !default You can assign to variables if they aren’t already assigned by adding the !default flag

& in SassScript Just like when it’s used in selectors, & in SassScript refers to the current parent selector