anchor.diff: +/// Utilities for reading/modifying dynamic keys on JavaScript objects
  +/// and converting Dart [Map]s to JavaScript objects.
   library react_client.js_interop_helpers;
   
   import "package:js/js.dart";
  
positive.code: typedef dynamic _GetPropertyFn(jsObj, String key);
  typedef dynamic _SetPropertyFn(jsObj, String key, value);
  
  // Necessary because `external operator[]` isn't allowed on JS interop classes https://github.com/dart-lang/sdk/issues/25053
  final _GetPropertyFn getProperty = (() {
    _eval(r'''
      function _getProperty(obj, key) {
  
negative.code:   return _getProperty;
  })();
  
  /// Sets the property at the given [_SetPropertyFn.key] to [_SetPropertyFn.value]
  /// on the specified JavaScript object [_SetPropertyFn.jsObj]
  ///
  /// Necessary because `external operator[]=` isn't allowed on JS interop classes
  /// (see: https://github.com/dart-lang/sdk/issues/25053).
  final _SetPropertyFn setProperty = (() {
    _eval(r'''
      function _setProperty(obj, key, value) {
  