Preserve attributes on table paste

[seleckis]

I have a table where all cells have "data-sync-id" attributes with unique values. When I copy/paste a table from another source (e.g. excel table), these attributes are being removed. How to preserve them on paste?

I extend TableCell extension like this:

import TTTableCell from "@tiptap/extension-table-cell";

export const TableCell = TTTableCell.extend({
  addAttributes() {
    return {
      ...this.parent?.(),
      ["data-sync-id"]: {
        default: null,
        renderHTML: (attributes) => {
          if (!attributes["data-sync-id"]) {
            return null;
          }

          return {
            ["data-sync-id"]: attributes["data-sync-id"],
          };
        },
        parseHTML: (element) => {
          return element.getAttribute("data-sync-id");
        },
      },
    };
  },
});