FRP with flutter ?

flurp.dart

import 'dart:async';
import 'dart:ui';

final double devicePixelRatio = window.devicePixelRatio;

final Size logicalSize = window.physicalSize / devicePixelRatio;

final Rect physicalBounds = Offset.zero & (logicalSize * devicePixelRatio);

void main() {
  final time$ = new Stream.periodic( new Duration(seconds: 1), (value) => value);
  final value$ = time$.map((t)=>"Counter : $t");
  value$.map(buildView).listen((view) {
    window.render(view);
    window.scheduleFrame();
  });
}

Scene buildView(String text) => render(draw(buildParagraph(text)));

Scene render(Picture view) {
  final sceneBuilder = new SceneBuilder()
    ..pushClipRect(physicalBounds)
    ..addPicture(Offset.zero, view)
    ..pop();
  return sceneBuilder.build();
}

Picture draw(Paragraph p) {
  final recorder = new PictureRecorder();
  final canvas = new Canvas(recorder, physicalBounds);
  canvas.scale(devicePixelRatio, devicePixelRatio);
  canvas.drawParagraph(p, new Offset(100.0, 100.0));
  return recorder.endRecording();
}

Paragraph buildParagraph(String text) {
  final paragraphBuilder = new ParagraphBuilder(new ParagraphStyle())
    ..addText('$text');
  final p = paragraphBuilder.build()
    ..layout(new ParagraphConstraints(width: logicalSize.width));
  return p;
}