forEach method
Implementation
void forEach(void f(String key, dynamic value)) {
var entries = JS('', '#.entries()', this);
while (true) {
var entry = JS('', '#.next()', entries);
if (JS('bool', '#.done', entry)) return;
f(JS('String', '#.value[0]', entry),
convertNativeToDart_Dictionary(JS('', '#.value[1]', entry)));
}
}