Example code not working on iOS

[njovy]

When trying to run the example code from this repository, I encounter the following runtime error:

══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
The following _TypeError was thrown building Builder:
type 'Null' is not a subtype of type 'Pointer<NativeType>' in type cast

The relevant error-causing widget was:
  MaterialApp
  MaterialApp:file:///Users/captainpark/Developer/flutter/flutter_js/example/lib/main.dart:24:18

When the exception was thrown, this was the stack:
#0      JavascriptCoreRuntime.evaluate (package:flutter_js/javascriptcore/jscore_runtime.dart:75:34)
#1      JavascriptRuntime._setupConsoleLog (package:flutter_js/javascript_runtime.dart:103:5)
#2      JavascriptRuntime.init (package:flutter_js/javascript_runtime.dart:70:5)
#3      new JavascriptCoreRuntime (package:flutter_js/javascriptcore/jscore_runtime.dart:51:5)
#4      getJavascriptRuntime (package:flutter_js/flutter_js.dart:45:15)
#5      new _FlutterJsHomeScreenState (package:flutter_js_example/main.dart:41:7)
#6      FlutterJsHomeScreen.createState (package:flutter_js_example/main.dart:34:46)
#7      new StatefulElement (package:flutter/src/widgets/framework.dart:5812:60)
#8      StatefulWidget.createElement (package:flutter/src/widgets/framework.dart:779:38)
...     Normal element mounting (24 frames)
#32     Element.inflateWidget (package:flutter/src/widgets/framework.dart:4555:16)
#33     MultiChildRenderObjectElement.inflateWidget (package:flutter/src/widgets/framework.dart:7178:36)
#34     MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:7194:32)
...     Normal element mounting (188 frames)
#222    Element.inflateWidget (package:flutter/src/widgets/framework.dart:4555:16)
#223    MultiChildRenderObjectElement.inflateWidget (package:flutter/src/widgets/framework.dart:7178:36)
#224    MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:7194:32)
...     Normal element mounting (552 frames)
#776    Element.inflateWidget (package:flutter/src/widgets/framework.dart:4555:16)
#777    Element.updateChild (package:flutter/src/widgets/framework.dart:4020:18)
#778    _RawViewElement._updateChild (package:flutter/src/widgets/view.dart:481:16)
#779    _RawViewElement.mount (package:flutter/src/widgets/view.dart:505:5)
...     Normal element mounting (15 frames)
#794    Element.inflateWidget (package:flutter/src/widgets/framework.dart:4555:16)
#795    Element.updateChild (package:flutter/src/widgets/framework.dart:4020:18)
#796    RootElement._rebuild (package:flutter/src/widgets/binding.dart:1687:16)
#797    RootElement.mount (package:flutter/src/widgets/binding.dart:1656:5)
#798    RootWidget.attach.<anonymous closure> (package:flutter/src/widgets/binding.dart:1609:18)
#799    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:3056:19)
#800    RootWidget.attach (package:flutter/src/widgets/binding.dart:1608:13)
#801    WidgetsBinding.attachToBuildOwner (package:flutter/src/widgets/binding.dart:1346:27)
#802    WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:1331:5)
#803    WidgetsBinding.scheduleAttachRootWidget.<anonymous closure> (package:flutter/src/widgets/binding.dart:1317:7)
#807    _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:194:12)
(elided 3 frames from class _Timer and dart:async-patch)

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I expected the example app to run without throwing any exceptions, showing the sample JavaScript evaluation.