addExternalElementToElement method

Implementation

@override
List<Node>? addExternalElementToElement(
  Node element,
  Object? externalElement, {
  DOMTreeMap<Node>? treeMap,
  DOMContext<Node>? context,
}) {
  if (externalElement == null) return null;
  if (!element.isA<Element>()) return null;

  externalElement = resolveElements(
    externalElement,
    treeMap: treeMap,
    context: context,
    setTreeMapRoot: false,
  );

  if (externalElement is List) {
    var added = <Node>[];
    for (var e in externalElement) {
      if (e == null) continue;

      if (e is List) {
        var l = addExternalElementToElement(
          element,
          e,
          treeMap: treeMap,
          context: context,
        );
        if (l != null) {
          added.addAll(l);
        }
      } else {
        // `e` is `dynamic`: extension members (like `asJSAny`) can't be
        // resolved on it, so give it a static type first.
        final Object o = e;
        if (o.isA<Node>()) {
          var node = o as Node;
          element.appendChild(node);
          added.add(node);
        }
      }
    }
    return added;
  } else {
    var jsAny = externalElement.asJSAny;
    if (jsAny.isA<Node>()) {
      var node = jsAny as Node;
      element.appendChild(node);
      return [node];
    }
  }

  return null;
}