lil trick

dimension.scss

/*
  example:

  dimension(foo, bar, 2, 10px);
  - gets the value bar inside foo map
  - multiplies it by two
  - adds 10px
*/
$dimensions: (
  global: (
    gutter: 20px
  ),
);

@function dimension($keys...) {
  $value: $dimensions;

  @each $key in $keys {
    @if (type-of($key) == number) {
      @if (unitless($key) == true) {
        $value: $value * $key;
      } @else if (unitless($key) == false) {
        $value: $value + $key;
      }
    }

    @if (type-of($key) == string) {
      $value: map-get($value, $key);
    }
  }

  @return $value;
}