CSS font weight with names

_weights.scss

/// Named Font Weights
///
/// @param {string} $name
///   the name of the weight, as such:
///   * thin
///   * extralight
///   * light
///   * book / regular
///   * medium
///   * semibold
///   * bold
///   * extrabold
///   * black
///
/// @return {Number}
///
/// @example scss
///   h1,h2,h3 {
///     font-weight: weight(medium);
///   }
///
/// @example css
///   h1,h2,h3 {
///     font-weight: 500;
///   }

@function weight($name) {
  @if      $name == thin                     { @return 100; }
  @else if $name == extralight               { @return 200; }
  @else if $name == light                    { @return 300; }
  @else if $name == book or $name == regular { @return 400; }
  @else if $name == medium                   { @return 500; }
  @else if $name == semibold                 { @return 600; }
  @else if $name == bold                     { @return 700; }
  @else if $name == extrabold                { @return 800; }
  @else if $name == black                    { @return 900; }

  @return 400;
}