$unit: 100ms;

$duration-data: (
  fast: $unit,
  base: $unit * 2,
  slow: $unit * 3,
  slower: $unit * 4,
  slowest: $unit * 5,
);

/// Returns the duration value for a given variant.
///
/// @param {String} $variant - The key for the given variant.
/// @return {Number} The spacing for the variant (in miliseconds).

@function duration($variant: base) {
  $fetched-value: map-get($duration-data, $variant);

  @if type-of($fetched-value) == number {
    @return $fetched-value;
  } @else {
    @error 'Duration variant `#{$variant}` not found. Available variants: #{available-names($duration-data)}';
  }
}