How do you pass variables to main in Dart?

Sounds like you are building a browser app?

(BTW, you can use new Options().arguments for command-line apps. Works great, but obviously there is no command line in browser apps :)

(Second, main() doesn't take arguments, so we have to find another way.)

OK, for a browser-app, what I might try doing is embedding some JSON into the page inside a <script> tag. Then, using query, find that element, parse the contents, and you're good to go.

In your HTML:

<script id="config">
  {"environment":"test"}
</script>

And in your Dart file:

import 'dart:html';
import 'dart:json' as json;

void main() {
  var config = json.parse(query("#config").innerHtml);

  print(config['environment']);
}

Hope that helps!