// For the date within the interval:
isWithinInterval(new Date(2014, 0, 3), {
start: new Date(2014, 0, 1),
end: new Date(2014, 0, 7)
})
//=> true
// For the date outside of the interval:
isWithinInterval(new Date(2014, 0, 10), {
start: new Date(2014, 0, 1),
end: new Date(2014, 0, 7)
})
//=> false