Function toggleValidCss

test/angular/1.2/angular.js:16334–16339

(isValid, validationErrorKey)

  // convenience method for easy toggling of classes
  function toggleValidCss(isValid, validationErrorKey) {
    validationErrorKey = validationErrorKey ? '-' + snake_case(validationErrorKey, '-') : '';
    $animate.setClass(element,
      (isValid ? VALID_CLASS : INVALID_CLASS) + validationErrorKey,
      (isValid ? INVALID_CLASS : VALID_CLASS) + validationErrorKey);
  }

  /**
   * @ngdoc method