A Sass mixin for setting position the same way that margin and padding are set (`null` is used where no value should be output)

_position.scss

/*
  Set position like margin/padding shorthand - rules with null value
  are removed from output (standard)

  Example:
    @include position(0 20px null, fixed);

  Output:
    position: fixed;
    top: 0;
    left: 20px;
    right: 20px;
*/

@mixin position($coordinates: 0, $position: absolute) {
  $length: length($coordinates);

  $top: nth($coordinates, 1);
  $right: nth($coordinates, 1);
  $bottom: nth($coordinates, 1);
  $left: nth($coordinates, 1);

  @if $length > 1 {
    $right: nth($coordinates, 2);
    $left: nth($coordinates, 2);
  }
  @if $length > 2 { $bottom: nth($coordinates, 3); }
  @if $length > 3 { $left: nth($coordinates, 4); }

  position: $position;

  top: $top;
  bottom: $bottom;
  left: $left;
  right: $right;
}

/*
  Example:
    @include position(10px null 0);

  Output:
    position: absolute;
    top: 10px;
    bottom: 0;
*/

/*
  Example:
    @include position;

  Output:
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
*/