function convert(t) {
const dt = new Date(t);
const hr = dt.getUTCHours();
const m = "0" + dt.getUTCMinutes();
return hr + ':' + m.substr(-2)
}
console.log(convert(1542895249079));
console.log(convert(1542897015049));
console.log(convert(1542902445344));