onDescribeNode method

Implementation

void onDescribeNode(int? id, Map<String, dynamic> params) {
  // https://chromedevtools.github.io/devtools-protocol/tot/DOM/#method-describeNode
  // Supports identifying by nodeId or backendNodeId. objectId is ignored for now.
  final ctx = dbgContext;
  if (ctx == null) {
    sendToFrontend(id, null);
    return;
  }

  Node? target;
  // Prefer nodeId if provided
  final int? nodeId = params['nodeId'];
  if (nodeId != null) {
    final targetId = ctx.getTargetIdByNodeId(nodeId);
    if (targetId != null && targetId != 0) {
      target = ctx.getBindingObject(Pointer.fromAddress(targetId)) as Node?;
    }
  }

  // Fallback to backendNodeId
  if (target == null) {
    final int? backendNodeId = params['backendNodeId'];
    if (backendNodeId != null && backendNodeId != 0) {
      target = ctx.getBindingObject(Pointer.fromAddress(backendNodeId)) as Node?;
    }
  }

  if (target == null) {
    sendToFrontend(id, null);
    return;
  }

  final int depth = (params['depth'] is int) ? (params['depth'] as int) : 1;

  Map<String, dynamic> toJsonWithDepth(Node n, int d) {
    final base = <String, dynamic>{
      'nodeId': n.ownerView.forDevtoolsNodeId(n),
      'backendNodeId': n.pointer?.address ?? 0,
      'nodeType': getNodeTypeValue(n.nodeType),
      'localName': n is Element ? n.tagName.toLowerCase() : null,
      'nodeName': n.nodeName,
      'nodeValue': n is TextNode
          ? (n as TextNode).data
          : (n is Comment ? (n as Comment).data : ''),
      'parentId': n.parentNode != null ? n.ownerView.forDevtoolsNodeId(n.parentNode!) : 0,
      'childNodeCount': n.childNodes.length,
      'attributes': n is Element
          ? (() {
              final attrs = <String>[];
              (n as Element).attributes.forEach((k, v) {
                attrs.add(k);
                attrs.add(v.toString());
              });
              return attrs;
            })()
          : null,
    };
    // Remove nulls to match prior InspectorNode encoding
    base.removeWhere((k, v) => v == null);

    if (d > 0 && n.childNodes.isNotEmpty) {
      final list = <Map<String, dynamic>>[];
      for (final c in n.childNodes) {
        if (c is Element || (c is TextNode && c.data.trim().isNotEmpty)) {
          list.add(toJsonWithDepth(c, d - 1));
        }
      }
      if (list.isNotEmpty) base['children'] = list;
    }
    return base;
  }

  final result = {'node': toJsonWithDepth(target, depth)};
  sendToFrontend(id, JSONEncodableMap(result));
}