Choosing between `Option` and `Effect` for code involving `X`

export const findIndex = (self: X): O.Option<number> =>
    ROA.findFirstIndex(Xs, Equal.equals(self));

export const isFormY = (
    a: X,
    b: X,
    c: X,
): O.Option<boolean> => {
    const modularQuotient = (n: number) => Math.floor(mod(n + 1, 12) / 3);
    return O.Do().pipe(
        O.bind('indexA', () => findIndex(a)),
        O.bind('indexB', () => findIndex(b)),
        O.bind('indexC', () => findIndex(c)),
        O.map(
            ({ indexA, indexB, indexC }) =>
                modularQuotient(indexA) === modularQuotient(indexB) &&
                modularQuotient(indexB) === modularQuotient(indexC),
        ),
    );
};