[Feature Request] Add SortDirection parameter to custom SortingFn

[rpiaggio]

We have cases where we want certain values to always be sorted at the end despite of sort direction.

This can be achieved by passing the column sort direction to a custom sorting function, where we can treat this case.

Eg, have SortingFn's signature be:

export type SortingFn<TData extends AnyData> = {
  (rowA: Row<TData>, rowB: Row<TData>, columnId: string, direction: SortDirection): number
}

It seems this could help other users too (#3300).

Thank you!

[jodoox]

@tannerlinsley Huge fan of your libraries, thanks for all these contributions.

Having undefined values at the bottom of the list regardless of the direction is a reasonable need, yet I believe it is not possible to achieve it easily with the custom sorting functions as of now. Exposing the sort direction seems like a simple yet useful addition that would solve this issue, would you be open to a PR for this?

[artchen-db]

+1 I too think sorting "null values" always at bottom is a reasonable feature to support, and passing sort direction to the sorting function is essential to implementing this feature.

[jodoox]

I solved it for the moment with this helper sortingFn: categoricalSortingFn(table, ["high", "medium", "low"])
Got no answer on the discord as well

export const categoricalSortingFn = <RowType extends Record<string, unknown>>(
  table: Table<RowType> | null,
  values: string[],
): SortingFn<RowType> => {
  return (rowA: Row<RowType>, rowB: Row<RowType>, columnId: string) => {
    const desc = table?.getState().sorting.find((x) => x.id === columnId)?.desc;
    const sortedArray = desc ? [...values, undefined] : [undefined, ...values];
    const valA = rowA.getValue<string | undefined>(columnId);
    const valB = rowB.getValue<string | undefined>(columnId);
    const iA = sortedArray.indexOf(valA);
    const iB = sortedArray.indexOf(valB);
    const order = iA < iB ? 1 : -1;
    return order;
  };
};

[artchen-db]

Thanks! This approach of passing a ref to the table model works great in our use case too.

[artchen-db]

I was reading some old issues like #2371, it seems the direction was part of the function signature. It would be great if we could bring it back.

[sullyslegacy]

The sortEntry has id and desc however only id is being passed to the sortingFn. It would be very helpful if desc was passed in as well.

However a workaround would be doing something like
`
sortingFn: (obj1: Row, obj2: Row, prop: string) =>
sortUndefinedAtBottom(
customValueFunction(obj1.original),
customValueFunction(obj2.original),
isColumnSortedDesc(obj1, prop)
),

const isColumnSortedDesc = <T,>(column: Row, prop: string) => {
const sort = column._getAllCellsByColumnId()[prop].column.getIsSorted();
return sort === ('desc' as SortDirection);
};

const sortUndefinedAtBottom = (value1: number | undefined, value2: number | undefined, isSortedDesc: boolean) => {
if (value1 === value2) {
return 0;
}

if (value1 === undefined) {
    return isSortedDesc ? -1 : 1;
} else if (value2 === undefined) {
    return isSortedDesc ? 1 : -1;
}

return value1 - value2;

};
`

[inomn]

Hi! In case you want to sort columns with range values, for example [241, 567], and for ascending I would like to compare rows by 1st value (241), but for descending by last (567).

It is not possible to write a custom sorting function to achieve that without having sortDirection.
I would appreciate adding sortDirection to sortingFn signature.