Dart by Example: Function Types

typedef bool Validator(int n);
bool positive(int n) => n >= 0;
bool lessThan100(int n) => n < 100;
bool bothValid(int n, Validator v1, Validator v2) {
  return v1(n) && v2(n);
}
main() {
  Validator both = (int n) => bothValid(n, positive, lessThan100);
  print('${both(5)}');
  print('${both(1000)}');
}
 

$ dart typedef.dart
true
false

by @jryanio | source | license