[javascript] Convert HH:MM:SS string to seconds only in javascript

I am having similar requirement as this: Convert time in HH:MM:SS format to seconds only?

but in javascript. I have seen many examples of converting seconds into different formats but not HH:MM:SS into seconds. Any help would be appreciated.

You can do this dynamically - in case you encounter not only: HH:mm:ss, but also, mm:ss, or even ss alone.

var str = '12:99:07';
var times = str.split(":");
times.reverse();
var x = times.length, y = 0, z;
for (var i = 0; i < x; i++) {
    z = times[i] * Math.pow(60, i);
    y += z;
}
console.log(y);

Javascript's static method Date.UTC() does the trick:

alert(getSeconds('00:22:17'));

function getSeconds(time)
{
    var ts = time.split(':');
    return Date.UTC(1970, 0, 1, ts[0], ts[1], ts[2]) / 1000;
}

Here is maybe a bit more readable form on the original approved answer.

const getSeconds = (hms: string) : number => {
  const [hours, minutes, seconds] = hms.split(':');
  return (+hours) * 60 * 60 + (+minutes) * 60 + (+seconds);
};

This function handels "HH:MM:SS" as well as "MM:SS" or "SS".

function hmsToSecondsOnly(str) {
    var p = str.split(':'),
        s = 0, m = 1;

    while (p.length > 0) {
        s += m * parseInt(p.pop(), 10);
        m *= 60;
    }

    return s;
}

Convert hh:mm:ss string to seconds in one line. Also allowed h:m:s format and mm:ss, m:s etc

'08:45:20'.split(':').reverse().reduce((prev, curr, i) => prev + curr*Math.pow(60, i), 0)

This can be done quite resiliently with the following:

'01:02:03'.split(':').reduce((acc,time) => (60 * acc) + +time);

This is because each unit of time within the hours, minutes and seconds is a multiple of 60 greater than the smaller unit. Time is split into hour minutes and seconds components, then reduced to seconds by using the accumulated value of the higher units multiplied by 60 as it goes through each unit.

The +time is used to cast the time to a number.

It basically ends up doing: (60 * ((60 * HHHH) + MM)) + SS

If only seconds is passed then the result would be a string, so to fix that we could cast the entire result to an int:

+('03'.split(':').reduce((acc,time) => (60 * acc) + +time));

This function works for MM:SS as well:

const convertTime = (hms) => {_x000D_
        if (hms.length <3){_x000D_
         return hms_x000D_
        } else if (hms.length <6){_x000D_
          const a = hms.split(':')_x000D_
          return hms = (+a[0]) * 60 + (+a[1])_x000D_
        } else {_x000D_
          const a = hms.split(':')_x000D_
          return hms = (+a[0]) * 60 * 60 + (+a[1]) * 60 + (+a[2])_x000D_
        }_x000D_
      }

Since the getTime function of the Date object gets the milliseconds since 1970/01/01, we can do this:

var time = '12:23:00';
var seconds = new Date('1970-01-01T' + time + 'Z').getTime() / 1000;

new Date(moment('23:04:33', "HH:mm")).getTime()

Output: 1499755980000 (in millisecond) ( 1499755980000/1000) (in second)

Note : this output calculate diff from 1970-01-01 12:0:0 to now and we need to implement the moment.js

This is the most clear, easy to understand solution:

function convertDurationtoSeconds(duration){
    const [hours, minutes, seconds] = duration.split(':');
    return Number(hours) * 60 * 60 + Number(minutes) * 60 + Number(seconds);
};

const input = '01:30:45';
const output = convertDurationtoSeconds(input);
console.log(`${input} is ${output} in seconds`);

try

time="12:12:12";
tt=time.split(":");
sec=tt[0]*3600+tt[1]*60+tt[2]*1;

Taken from the solution given by Paul https://stackoverflow.com/a/45292588/1191101 but using the old function notation so it can also be used in other js engines (e.g. java Rhino)

function strToSeconds (stime)
{
   return +(stime.split(':').reduce(function (acc,time) { return +(60 * acc) + +time }));
}

or just this one more readable

function strToSeconds (stime)
{
  var tt = stime.split(':').reverse ();
  return ((tt.length >= 3) ? (+tt[2]): 0)*60*60 + 
         ((tt.length >= 2) ? (+tt[1]): 0)*60 + 
         ((tt.length >= 1) ? (+tt[0]): 0);
}