How to convert JavaScript object to Dart Map?

Question

I am looking for some reverse of new JsObject.jsify. Something, that would convert javascript Object back to Dart Map Is there something like that available?

I know that I can use JSON conversion to string, but this does not address transfer of Objects containing functions, Dart objects, Dom Elements, etc... Is there any better method?

Answer 1

Here's an adapter to handle a JsObject like a Map<String, dynamic> :

import 'dart:collection' show Maps;
import 'dart:js';

class JsMap implements Map<String,dynamic> {
  final JsObject _jsObject;
  JsMap.fromJsObject(this._jsObject);

  operator [](String key) => _jsObject[key];
  void operator []=(String key, value) {
    _jsObject[key] = value;
  }
  remove(String key) {
    final value = this[key];
    _jsObject.deleteProperty(key);
    return value;
  }
  Iterable<String> get keys => context['Object'].callMethod('keys', [_jsObject]);

  // use Maps to implement functions
  bool containsValue(value) => Maps.containsValue(this, value);
  bool containsKey(String key) => keys.contains(key);
  putIfAbsent(String key, ifAbsent()) => Maps.putIfAbsent(this, key, ifAbsent);
  void addAll(Map<String, dynamic> other) {
    if (other != null) {
      other.forEach((k,v) => this[k] = v);
    }
  }
  void clear() => Maps.clear(this);
  void forEach(void f(String key, value)) => Maps.forEach(this, f);
  Iterable get values => Maps.getValues(this);
  int get length => Maps.length(this);
  bool get isEmpty => Maps.isEmpty(this);
  bool get isNotEmpty => Maps.isNotEmpty(this);
}