Arrow Functions - Dart Programming

When a function's body is a single expression, => is shorthand for { return expr; }. The block form and the arrow form behave identically; arrow is just more concise.

Program

Play the program to call a block-body and an arrow-body version of the same idea.

arrow_functions.dart

int squareBlock(int n) {
  return n * n;
}

int squareArrow(int n) => n * n;

void main() {
  var a = squareBlock(5);
  var b = squareArrow(6);
  print('$a $b');
}

arrow body `fn(x) => expr` is shorthand for `{ return expr; }` when the body is one expression.

implicit return There is no `return` keyword in an arrow body; the expression's value is returned.

equivalent semantics Block-body and arrow-body produce the same call result; arrow is just terser.