text: // @flow
  
  const isPageNameValid = (initialPageName: string, pageName: string) => {
      if (pageName === initialPageName) {
          return false;
      }
  
      const decoded = decodeURI(pageName);
  
      if (decoded.startsWith('/') || decoded.startsWith(' ')) {
          return false;
      }
  
      if (decoded.includes('..') || decoded.includes('//') || decoded.includes('?') || decoded.includes('!')){
          return false;
      }
  
      if (decoded.endsWith('/') || decoded.endsWith('.') || decoded.endsWith(' ')) {
          return false;
      }
  
      return decoded.match(/^[0-9a-zA-Z.\-_/ ]+$/);
  };
  
  export default isPageNameValid;
  