export const getNewValue = ( action: '+' | '-', current: number, itemsLength: number, perScroll: number, perView: number, ): number => { const additional = perView - 1; if (action === '+') { if (current + additional === itemsLength) return 1; if (current + perScroll >= itemsLength) return itemsLength - additional; return current + perScroll; } if (current === 1) return itemsLength - additional; if (current - perScroll < 1) return 1; return current - perScroll; }; export const defaultProps = [ { header: 'Element №1', text: 'This is the first element.', }, { header: 'Element №2', text: 'Oh...one more!', }, { header: 'Element №3', text: 'I feel sick.....', }, ];