Expanding the selection to the active mark?

So based on comments above, this is fixed code. Is this right?

function linkAround(doc, pos) {
  let $pos = doc.resolve(pos);

  let start = $pos.parent.childAfter($pos.parentOffset);
  if (!start.node) {
    return;
  }

  let link = start.node.marks.find((mark) => mark.type === this.$editorView.state.schema.marks.link);
  if (!link) {
    return;
  }

  let startIndex = $pos.index();
  let startPos = $pos.start() + start.offset;
  while (startIndex > 0 && link.isInSet($pos.parent.child(startIndex - 1).marks)) {
    startIndex -= 1;
    startPos -= $pos.parent.child(startIndex).nodeSize;
  }

  let endIndex = $pos.indexAfter();
  let endPos = startPos + start.node.nodeSize;
  while (endIndex < $pos.parent.childCount && link.isInSet($pos.parent.child(endIndex).marks)) {
    endPos += $pos.parent.child(endIndex).nodeSize;
    endIndex += 1;
  }

  return {from: startPos, to: endPos};
}