How to Combine Date and Time into a Single Object

How to combine date and time into a single object?

You just need to use the correct methods, instead of calling constructors. Use parse to create local date and local time objects, then pass the two objects to the of method of LocalDateTime:

    LocalDate datePart = LocalDate.parse("2013-01-02");
    LocalTime timePart = LocalTime.parse("04:05:06");
    LocalDateTime dt = LocalDateTime.of(datePart, timePart);

EDIT

Apparently, you need to combine two Date objects instead of 2 strings. I guess you can first convert the two dates to strings using SimpleDateFormat. Then use the methods shown above.

String startingDate = new SimpleDateFormat("yyyy-MM-dd").format(startDate);
String startingTime = new SimpleDateFormat("hh:mm:ss").format(startTime);

How to combine date and time into a single datetime object?

You can specify the format of your input string to let moment know how to parse it.

var date = '2019-02-16';var time = '8:24 PM';
// tell moment how to parse the input stringvar momentObj = moment(date + time, 'YYYY-MM-DDLT');
// conversionvar dateTime = momentObj.format('YYYY-MM-DDTHH:mm:s');
console.log(dateTime);

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>

R tick data : merging date and time into a single object

Create a datetime object with as.POSIXct:

as.POSIXct(paste(x$date, x$time), format="%Y-%m-%d %H:%M:%S")
[1] "2010-02-02 08:00:03 GMT" "2010-02-02 08:00:04 GMT" "2010-02-02 08:00:04 GMT"
[4] "2010-02-02 08:00:04 GMT" "2010-02-02 08:00:04 GMT"

How to combine date portion of one date and combine it with time portion of another date

Assuming your dates are in the ISO format and need another ISO date string as the result:

function start (date, time) {
    return `${date.split("T")[0]}T${time.split("T")[1]}`;
}

console.log(start("2021-05-25T09:50:40.603Z", "2021-05-12T11:52:40.603Z"));

How to combine date and time into a Date object?

The Date() constructor always works fine with string as Shyne also told it permits only valid ISO formatted string.
There are 4 ways of creating Date objects with Date() constructor, and one of those is:
new Date(year, month, day, hours, minutes, seconds, milliseconds)

Considering your specific problem, a function can be written as:

function parseStringToDate(dateStr, timeStr) {

    // create array of DD, MM, YYYY
    let date = dateStr.split("-");

    // convert timeStr to string if is in float value with fixed 2 decimal points
    if (typeof (timeStr) !== 'string') {
        timeStr = timeStr.toFixed(2).toString();
    }
    let time = timeStr.replace(".", ":");    // "." --> ":"

    date.push(time);    // ['07', '07', '2021', '8:30']
    console.log(new Date(date).toString());
}

parseStringToDate('07-07-2021', '8.30');
parseStringToDate('07-07-2021', 8.00);

combine date and time into a single datetime

Pass your date and time to this function. It will return the Date object. Use getTime() on that to get the desired result. Codepen example.

function getAsDate(day, time)
{
 var hours = Number(time.match(/^(\d+)/)[1]);
 var minutes = Number(time.match(/:(\d+)/)[1]);
 var AMPM = time.match(/\s(.*)$/)[1];
 if(AMPM == "pm" && hours<12) hours = hours+12;
 if(AMPM == "am" && hours==12) hours = hours-12;
 var sHours = hours.toString();
 var sMinutes = minutes.toString();
 if(hours<10) sHours = "0" + sHours;
 if(minutes<10) sMinutes = "0" + sMinutes;
 time = sHours + ":" + sMinutes + ":00";
 var d = new Date(day);
 var n = d.toISOString().substring(0,10);
 var newDate = new Date(n+"T"+time);
 return newDate;
}

Combine date and time string into single date with javascript

You can configure your date picker to return format like YYYY-mm-dd (or any format that Date.parse supports) and you could build a string in timepicker like:

 var dateStringFromDP = '2013-05-16';

 $('#timepicker').timepicker().on('changeTime.timepicker', function(e) {
    var timeString = e.time.hour + ':' + e.time.minute + ':00';
    var dateObj = new Date(datestringFromDP + ' ' + timeString);
  });

javascript Date object takes a string as the constructor param

How to Combine Date and Time into a Single Object