src/Drupal/Core/Template/Attribute.php
public function removeClass() {
    // With no class attribute, there is no need to remove.
    if (isset($this->storage['class']) && $this->storage['class'] instanceof AttributeArray) {
      $args = func_get_args();
      $classes = array();
      foreach ($args as $arg) {
        // Merge the values passed in from the classes array.
        // The argument is cast to an array to support comma separated single
        // values or one or more array arguments.
        $classes = array_merge($classes, (array) $arg);
      }

      // Remove the values passed in from the value array. Use array_values() to
      // ensure that the array index remains sequential.
      $classes = array_values(array_diff($this->storage['class']->value(), $classes));
      $this->storage['class']->exchangeArray($classes);
    }
    return $this;
  }
public function removeClass() {
    // With no class attribute, there is no need to remove.
    if (isset($this->storage['class']) && $this->storage['class'] instanceof AttributeArray) {
      $args = func_get_args();
      $classes = array();
      foreach ($args as $arg) {
        // Merge the values passed in from the classes array.
        // The argument is cast to an array to support comma separated single
        // values or one or more array arguments.
        $classes = array_merge($classes, (array) $arg);
      }

      // Remove the values passed in from the value array. Use array_values() to
      // ensure that the array index remains sequential.
      $classes = array_values(array_diff($this->storage['class']->value(), $classes));
      $this->storage['class']->exchangeArray($classes);
    }
    return $this;
  }
public function removeClass ( ) { // With no class attribute, there is no need to remove. if ( isset ( $ this -> storage [ 'class' ] ) && $ this -> storage [ 'class' ] instanceof AttributeArray ) { $ args = func_get_args ( ) ; $ classes = array ( ) ; foreach ( $ args as $ arg ) { // Merge the values passed in from the classes array. // The argument is cast to an array to support comma separated single // values or one or more array arguments. $ classes = array_merge ( $ classes , ( array ) $ arg ) ; } // Remove the values passed in from the value array. Use array_values() to // ensure that the array index remains sequential. $ classes = array_values ( array_diff ( $ this -> storage [ 'class' ] -> value ( ) , $ classes ) ) ; $ this -> storage [ 'class' ] -> exchangeArray ( $ classes ) ; } return $ this ; }
Removes argument values from array of existing CSS classes.

@param string|array ...
CSS classes to remove from the class attribute array.

@return $this
Removes argument values from array of existing CSS classes .