@mixin dropdown_arrow($size, $offset, $location, $direction) {

  $opposite_location: 'top';
  @if $location == 'top' {
    $opposite_location: 'bottom';
  }

  $opposite_direction: 'left';
  @if $direction == 'left' {
    $opposite_direction: 'right';
  }

  &:before, &:after {
    position: absolute;
    content: '';
  }

  // Defaults the arrow to the left side
  &:before {
    #{$location}: ($size + 1) * -1;
    #{$direction}: $offset - 1;
    #{$opposite_location}: auto;
    #{$opposite_direction}: auto;
    border-#{$opposite_direction}: ($size + 1) solid transparent;
    border-#{$opposite_location}: ($size + 1) solid $dropdown-border;
    border-#{$direction}: ($size + 1) solid transparent;
    border-#{$location}: 0;
    border-#{$opposite_location}-color: rgba(0, 0, 0, 0.2);
  }
  &:after {
    #{$location}: -$size;
    #{$direction}: $offset;
    #{$opposite_location}: auto;
    #{$opposite_direction}: auto;
    border-#{$opposite_direction}: $size solid transparent;
    border-#{$opposite_location}: $size solid $body-bg;
    border-#{$direction}: $size solid transparent;
    border-#{$location}: 0;
  }
}

.dropdown-menu {
  @include dropdown_arrow($dropdown-arrow-size, $dropdown-arrow-offset, 'top', 'left');
}

.dropdown-menu-right {
  @include dropdown_arrow($dropdown-arrow-size, $dropdown-arrow-offset, 'top', 'right');
}

.dropup > .dropdown-menu {
  @include dropdown_arrow($dropdown-arrow-size, $dropdown-arrow-offset, 'bottom', 'left');
}

.dropup > .dropdown-menu-right {
  @include dropdown_arrow($dropdown-arrow-size, $dropdown-arrow-offset, 'bottom', 'right');
}