Mida võimaldavad teha konstantsed konstruktorid Dartis?

Konstant constructors in Dart allow creating objects that are compile-time constants. This means that the value of the object is known during compilation, not just at runtime.

Advantages of using constant constructors:

• Performance: Objects created with constant constructors are cached by the compiler. If multiple identical constant objects are created, they actually refer to the same instance in memory, reducing the costs of creating new objects and decreasing memory consumption.
• Efficiency: Enables code optimization during compilation.
• Use in constant expressions: Objects created with a constant constructor can be used in other constant expressions, such as in const declarations.

Conditions for using a constant constructor:

• All class fields must be final.
• The constructor body must be empty or contain only a call to the parent constructor (super()).
• The constructor must be marked with the keyword const.

Example:

class Point {
  final double x;
  final double y;

  // Constant constructor
  const Point(this.x, this.y);
}

void main() {
  // Creating constant objects
  const Point p1 = Point(0.0, 0.0);
  const Point p2 = Point(0.0, 0.0);

  // p1 and p2 refer to the same object in memory
  print(p1 == p2); // Will print true
}