code: function( context, target ) {
      var $$target = $.qsa( target || 'u, ins', context )
      var i = $$target.length
  
      traverse: while ( i-- ) {
        var $this = $$target[ i ]
        var $prev = null
  
        // Ignore all `<wbr>` and comments in between,
        // and add class `.adjacent` once two targets
        // are next to each other.
        ignore: do {
          $prev = ( $prev || $this ).previousSibling
  
          if ( !$prev ) {
            continue traverse
          } else if ( $$target[ i-1 ] === $prev ) {
            $this.classList.add( 'adjacent' )
          }
        } while ( $.isIgnorable( $prev ))
      }
    }
docs: Traverse all target elements and address presentational corrections if any two of them are adjacent to each other.