Move conversion utils to production code, for reusability

Author: EmilianoSanchez

splitio_web/lib/src/js_interop.dart

@@ -1,5 +1,7 @@
 import 'dart:js_interop';
 
+// JS SDK types
+
 @JS()
 extension type JS_IBrowserSDK._(JSObject _) implements JSObject {
 }
@@ -13,3 +15,39 @@ extension type JS_BrowserSDKPackage._(JSObject _) implements JSObject {
   external JSFunction? WarnLogger;
   external JSFunction? ErrorLogger;
 }
+
+// Conversion utils: JS to Dart types
+
+@JS('Object.keys')
+external JSArray<JSString> _objectKeys(JSObject obj);
+
+@JS('Reflect.get')
+external JSAny? _reflectGet(JSObject target, JSAny propertyKey);
+
+List<dynamic> jsArrayToList(JSArray obj) {
+  return obj.toDart.map(jsAnyToDart).toList();
+}
+
+Map<String, dynamic> jsObjectToMap(JSObject obj) {
+  return {
+    for (final jsKey in _objectKeys(obj).toDart)
+      // @TODO _reflectGet (js_interop) vs obj.getProperty (js_interop_unsafe)
+      jsKey.toDart: jsAnyToDart(_reflectGet(obj, jsKey)),
+  };
+}
+
+dynamic jsAnyToDart(JSAny? value) {
+  if (value is JSArray) {
+    return jsArrayToList(value);
+  } else if (value is JSObject) {
+    return jsObjectToMap(value);
+  } else if (value is JSString) {
+    return value.toDart;
+  } else if (value is JSNumber) {
+    return value.toDartDouble;
+  } else if (value is JSBoolean) {
+    return value.toDart;
+  } else {
+    return value; // JS null and undefined are null in Dart
+  }
+}

splitio_web/test/splitio_web_test.dart

@@ -7,7 +7,6 @@ import 'package:splitio_web/src/js_interop.dart';
 import 'package:splitio_platform_interface/split_configuration.dart';
 import 'package:splitio_platform_interface/split_sync_config.dart';
 import 'package:splitio_platform_interface/split_rollout_cache_configuration.dart';
-import 'utils/js_interop_test_utils.dart';
 
 extension on web.Window {
   @JS()