Is there a compiler preprocessor in Dart?

Question

Since a compilation is required before launching a dart application, i wonder if compiler preprocessor is available, or is scheduled in a near future for Dart.
My search

Answer 1

From http://blog.sethladd.com/2013/12/compile-time-dead-code-elimination-with.html

Suppose you have code like this:

log(String msg) {
  if (const String.fromEnvironment('DEBUG') != null) {
    print('debug: $msg');
  }
}

main() {
  log('In production, I do not exist');
}

When compiled with dart2js -DDEBUG=true app.dart, the output includes the logging behavior:

  main: function() {
    H.printString("debug: In the production release, I do not exist");
  }

(the log function is inlined, but the print still happens)

However, if -DDEBUG is not set, the logging behavior is not included in the generated JavaScript code:

  main: function() {
  }