dayPartsUtils.js

    function dayPartToMoment(dayPart) {
        return moment(dayPart, 'HHmm');
    }

    function momentAtDayPart(moment, dayPart) {
        return dayPartToMoment(dayPart).set({
            year: moment.year(),
            month: moment.month(),
            date: moment.date()
        });
    }

    function nextMomentAtDayPart(startMoment, dayPart) {
        const nextMoment = momentAtDayPart(startMoment, dayPart);

        if(nextMoment.isBefore(startMoment)) {
            nextMoment.add( {day: 1} );
        }

        return nextMoment;
    }

    function dayPartsToMoments(fromMomentDate, day_parts) {
        return day_parts.map(dayPart => {
            fromMomentDate = nextMomentAtDayPart(fromMomentDate, dayPart);
            return fromMomentDate;
        });
    }

    function momentsAsRanges(moments) {
        return moments.map((moment, idx) => {
            const nextMoment = idx < moments.length - 1 ? moments[idx + 1] : moments[0].clone().add({ days: 1 });
            return {
                start: moment,
                end: nextMoment
            };
        });
    }

        const day_parts = ['2200', '0200', '0700'];
        const dayPartMoments = dayPartsToMoments(moment(), day_parts);
        console.log(dayPartMoments);

        const dayPartRanges = momentsAsRanges(dayPartMoments);
        console.log(dayPartRanges);

        console.log(dayPartsToMoments(moment(), ['1730', '2215', '0201', '0700']));

        console.log(momentsAsRanges(dayPartsToMoments(moment(), ['0400'])));