Dart Academy · Lesson

Initializer Lists and Redirecting

Set finals and reuse constructors.

Setting final Fields

A final field must be set before the constructor body runs. The initializer list is the perfect place to give it its one value.

class Circle {
  final double area;
  Circle(double r) : area = 3.14 * r * r;
}

After the parameter list, add a colon and comma-separated assignments. This initializer list runs before the constructor body.

Point(int x, int y) : x = x, y = y;