Flutter & Dart: every() method example

A few examples of using the every() method ( Iterable class) in Dart (and Flutter) . The purpose of this method is to check whether each element of a given iteration satisfies one or more conditions (using a test function):

bool every(
   bool test(
     E element
   )
)

1. Check that each number in the list is divisible by 3 :

void main() {
  var myList = [0, 3, 6, 9, 18, 21, 81, 120];
  bool result1 = myList.every((element){
    if(element %3 ==0){
      return true;
    } else {
      return false; 
    }
  }); 
  
  // expectation: true
  print(result1); 
}

output:

true

2. Check that each name in the list contains the “m” character :

void main() {
  var names = ['Obama', 'Trump', 'Biden', 'Pompeo']; 
  bool hasM = names.every((element) {
     if(element.contains('m')) return true;
     return false;
  });
  
  print(hasM);
}

output:

false

You can find more details about every() method in the official documentation.