javascript - get date to closest x minutes

getClosestDateToMins.js

function getRange() {
    var lower = getLowerClosest(10);
    var upper = getHigherClosest(10);
    return moment(lower).format('HH:mm:ss') + ' - ' + moment(upper).format('HH:mm:ss');
}

function getLowerClosest(mins) {
    var coeff = 1000 * 60 * mins;
    var date  = new Date();
    return new Date(Math.floor(date.getTime() / coeff) * coeff);
}

function getHigherClosest(mins) {
    var coeff = 1000 * 60 * mins;
    var date  = new Date();
    return new Date(Math.ceil(date.getTime() / coeff) * coeff);
}

function getClosest(mins) {
    var coeff = 1000 * 60 * mins;
    var date  = new Date();
    return new Date(Math.round(date.getTime() / coeff) * coeff);
}