Defining a Function

함수 정의 및 실행

String sayHello(String name){
 return 'Hello $name nice to meet you!';
}

void main() {
  print(sayHello("steven"));
}

fat arrow syntax ({} 나 return이 필요 없게 된다.)

String sayHello(String name) => 'Hello $name nice to meet you!'; // fat arrow syntax => 바로 return하는 거랑 같은 의미

void main() {
  print(sayHello("steven"));
}

Named Parameters

String sayHello(String name ,int age, String country) {
  return 'Hello $name nice to meet you! you are $age and you come from $country'; 
}

void main() {
  print(sayHello("steven",25,'England')); 
}

not best practice (순서가 헷갈리거나 까먹을 수 있음)

String sayHello({required String name = 'anonymous' ,required int age = 99, required String country ='wakanda'}) {
  return 'Hello $name nice to meet you! you are $age and you come from $country'; 
}

void main() {
  print(sayHello(
    name : "steven",
    age : 25,
    country : "England"
  )); // Hello steven nice to meet you! you are 25 and you come from England
  print(sayHello()); // Hello anonymous nice to meet you! you are 99 and you come from wakanda
}

Optional positional parameters

String sayHello(String name, int age, [String? country = 'Wales']) =>
    'Hello $name nice to meet you! you are $age and you come from $country';

void main() {
  var result = sayHello(
    'Steven',
    25,
  );
  print(result); 
  // Hello Steven nice to meet you! you are 25 and you come from Wales
}