Implementation of palindrome in dart

palindrome.dart

import "dart:core"; 

void main() async {
  final mymap = {  
   'arara': true, 
   'racecar': true, 
   ')(()': true, 
   'radar': true,
   '()()': false,
  };
  
  
  for(var item in mymap.entries){
    print('${item.key} is palindrome? should be ${item.value} but  ${isPalindrome(item.key) }');
  }
}

bool isPalindrome(String phrase){
  final initialPhrase = phrase.replaceAll(RegExp(r'\W'), '').toLowerCase();
  final reversedPhrase = initialPhrase.split('').reversed.join();
  
  return initialPhrase == reversedPhrase;
}