main.dart

void main() {
  var person = {
    "name" : "Marcin",
    "age" : 48,
    "foot": "left"
  };
  
  var updates = {
    "name": "Kaks",
    "age": 25,
    "playingStyle": "Agressive"
  };
  
  print("Original:");
  print(person);
  
  print("After merge:");
  print({...person, ...updates});
}