export default ( [incA1, incA2]: [number, number], [incB1, incB2]: [number, number] ) => { const al = Math.min(incA1, incA2); const au = Math.max(incA1, incA2); const bl = Math.min(incB1, incB2); const bu = Math.max(incB1, incB2); const il = Math.max(al, bl); const iu = Math.min(au, bu); if (il <= iu) { return [il, iu] as const; } return undefined; };