Subtracting seconds from the time in Javascript

I need to create a second function that will subtract recorded time from this in seconds. Currently, this function will display time as event_time: 02:24:25 which is great, I just need to take my recorded time in seconds e.g. 85 seconds and subtract from this value.

so if DateTimeFun is 02:24:25 and recordedTime = 60, the new function would return 02:23:25, subtracting 1 minute.

let recordedTime = parseInt(inputData.new_value) - parseInt(inputData.previous_value);

let dateTimeFun = function (d) {
    let h = d.getHours();
    let m = d.getMinutes();
    let s = d.getSeconds();

    if (h < 10) h = '0' + h;
    if (m < 10) m = '0' + m;
    if (s < 10) s = '0' + s;

    return h + ':' + m + ':' + s;
}