const routesList = [
{ exact: true, component: 123 },
{ path: '/test', exact: true, component: 321 },
];
routesList.map((route, index, routes) => ({
...route,
first: (!routes.some(route => route.first) && index === 0),
last: (!routes.some(route => route.last) && index === routes.length - 1),
path: route.path || `/${index + 1}`
}))