I have this pubspec.yaml
name: Dart Pages
description: The Dart platform.
dependencies:
web_compon
I had something similar here, with the js-interop package. I changed the ':' to '/' and it worked.
Original declaration:
import("package:mongo_dart/mongo_dart.dart");
Modified declaration:
#import("package/mongo_dart/mongo_dart.dart");
You could also try this (It has worked to me):
import 'packages/mongo_dart/mongo_dart.dart';