src/language-js/comments.js/handleObjectPropertyAssignment
function handleObjectPropertyAssignment({
  comment,
  precedingNode,
  enclosingNode,
}) {
  if (
    enclosingNode &&
    (enclosingNode.type === "ObjectProperty" ||
      enclosingNode.type === "Property") &&
    enclosingNode.shorthand &&
    enclosingNode.key === precedingNode &&
    enclosingNode.value.type === "AssignmentPattern"
  ) {
    addTrailingComment(enclosingNode.value.left, comment);
    return true;
  }
  return false;
}