Top 10 Function that puzzle developers new to Flutter (Darts)

Dollar sign ($) -  $string1/{exp1}

Putting a dollar syntax/sign in front of a variable or expression would tell compiler to look at value of var/exp.  In essence, String Interpolation.

e.g.

Input:

String food1 = "Burger"

String food2 = "sushi"

print('My favourite food1 is $food and ${food2.upper()}');

Output:

Burger

SUSHI

Cascade Notation (..)
Been seeing methods with double dots preceding e.g. ..add()/..remove() lurking around and can't figure out whether it is deliberate or typo.  Fret not, its not a typo.

Cascade notation allows you to combine multiple method of the same class in an expression without repeating the classname/prefix. i.e. chain methods

Example below:

myTable.add("Name");
myTable.add("Address");

myTable.add("Mobile");
myTable.remove("Fax");

Cascade Notation:

myTable..add("Name")..add("Address")..add("Mobile")..remove("Fax")

Async*

Ever thought why Async comes with a * operator/syntax.

This is to implement an asynchronous generator function which lazily produce a sequences of value.  A stream object would be return.

e.g.

Stream<int> test(int i) async* {

  int count = 0;

  while (count < i) yield count++;

}

Same goes for Sync* which returns an iterable object.

?.  Operator e.g. Obj1?.method1
This operator goes by many names; Unary Post-fix or Conditional member access.
Regardless, it does only one thing, check if object i.e. left operand is not null, execute method1.