DART

flutter datatypes check

void main(){
  var a = 'Apple';
  var b = 100;
  var c = [1, 2, 3, 4, 5];
  var d = {
    "name": "John Doe",
    "age" : 40
  };
  var e = 1.14;
  
  print(a.runtimeType);
  print(b.runtimeType);
  print(c.runtimeType);
  print(d.runtimeType); 
  print(e.runtimeType);
}

check data type flutter

selector.runtimeType // return data type of the variable

Example:
if (selector.runtimeType == int) print("Hello")