unable to use query giving error

[loveleet-convivity]

{
type: "relationship",
relationTo: "categoriessubitem",
name: "child",
admin: {
position: "sidebar",
},
hasMany: false,
filterOptions: ({ data }) => {
console.log("hjk", data);
return {
'parent.id': { equals: data?.categoriesitem },
};
},
},

[matthijs166]

Have you already tried something like the following? Don't think you need to reference the ID there:

const field = {
  type: "relationship",
  relationTo: "categoriessubitem",
  name: "child",
  admin: {
    position: "sidebar",
  },
  hasMany: false,
  filterOptions: ({ data }) => {
    return {
      "parent": { 
        equals: data?.categoriesitem.id // or data?.categoriesitem
      },
    };
  },
};