Dart Academy · Lesson

Factory and const Constructors

Cache, return subtypes, or build compile-time objects.

What a factory Constructor Is

A factory constructor looks like a normal one but you control what it returns, so it does not have to build a brand-new object every time.

class Logger {
  factory Logger() => _shared;
}

Because it returns rather than always creating, a factory can hand back a cached instance, perfect for singletons or pools.

class Logger {
  static final _it = Logger._();
  Logger._();
  factory Logger() => _it;
}