Flutter web support

While the general architectural concepts apply to all platforms that Flutter
supports, there are some unique characteristics of Flutter’s web support that
are worthy of comment.

Dart has been compiling to JavaScript for as long as the language has existed,
with a toolchain optimized for both development and production purposes. Many
important apps compile from Dart to JavaScript and run in production today,
including the advertiser tooling for Google Ads.
Because the Flutter framework is written in Dart, compiling it to JavaScript was
relatively straightforward.