javascript - adding elements of time array

Question

I have an array consisting of time durations like ['00:30', '01:30', '03:00', '04:30'] and I am trying to add the array elements to get total time duration. I am trying the below code to do this job but I am getting a irrelevant output like 00000.5010.503040.5:0. Have anyone tried this kind of sum earlier?

function calc_tot_dur() {
  var total_durs = ['00:30', '01:30', '03:00', '04:30'];
  var dim = '00:00';
  jQuery.each(total_durs, function(index, value) {
    //console.log(value);
    dim_split = dim.split(":");
    hs = dim_split[0];
    ms = dim_split[1];

    value_split = value.split(":");
    v_hs = value_split[0];
    v_ms = value_split[1];
    console.log(hs + v_hs);
    dim = (hs + v_hs) + ':' + (ms + v_ms);
    // console.log(dim);
    ms_hs = (ms + v_ms) / 60;
    if (ms_hs > 0) {
      dim = (hs + v_hs + ms_hs) + ':' + (00);
    } else {
      dim = (hs + v_hs) + ':' + (ms + v_ms);
    }
  });
  alert(dim);
}

yes, and on top of that, you are splliting AND modifying the dim variable for every iteration of the loop. — Peter B
– Peter B, Commented Apr 25, 2016 at 10:56
adding strings leads to concatenating them. You need to be converting them to numbers to add them — MohamedSanaulla
– MohamedSanaulla, Commented Apr 25, 2016 at 10:58

Nina Scholz · Accepted Answer · 2016-04-25 11:28:27Z

2

A solution with reduce and a correction for the length of the parts.

var total_durs = ['00:30', '01:30', '03:00', '04:30'],        
    result = function (array) {
        var total = array.reduce(function (r, a) {
                var aa = a.split(':').map(Number);
                return r + 60 * aa[0] + aa[1];
            }, 0);
			
        return [Math.floor(total / 60), total % 60].map(function (a) {
            var s = a.toString();
            return s.length < 2 ? '0' + s : s;
        }).join(':');
    }(total_durs);

document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');

answered Apr 25, 2016 at 11:28

Nina Scholz

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1 Comment

Ajay Narain Mathur Over a year ago

thumbs up for correction for the length of the parts

mohamed-ibrahim · Accepted Answer · 2016-04-25 11:06:32Z

You only miss some parseInt in some places so when you sum

"00" + "00" //as string it become 0000
parseInt("00") + parseInt("00") //will become 0

so the change:

function calc_tot_dur() {
  var total_durs = ['00:30', '01:30', '03:00', '04:30'];
  var dim = '00:00';
  jQuery.each(total_durs, function(index, value) {      
    dim_split = dim.split(":");
    hs = parseInt(dim_split[0]);   // here
    ms = parseInt(dim_split[1]);   // here   

    value_split = value.split(":");
    v_hs = parseInt(value_split[0]);   // here
    v_ms = parseInt(value_split[1]);   // here
    dim = (hs + v_hs) + ':' + (ms + v_ms);

    ms_hs = parseInt((ms + v_ms) / 60);   // here
    if (ms_hs > 0) {
      dim = (hs + v_hs + ms_hs) + ':' + (00);
    } else {
      dim = (hs + v_hs) + ':' + (ms + v_ms);
    }
 });
 console.log(dim);
}

Maloric · Accepted Answer · 2016-04-25 11:10:36Z

You could try using Moment, which is a great library for handling dates and durations in javascript. Here is a fiddle showing it in action:

https://jsfiddle.net/25zfe4h1/

function calc_tot_dur() {
  var total_durs = ['00:30', '01:30', '03:00', '04:30'];
  var dim = '00:00';
  jQuery.each(total_durs, function(index, value) {
    var duration = moment.duration(value);
    dim = moment.duration(dim).add(duration);
  });
  alert(formatResult(dim));
}

function formatResult(res) {
  return res.hours() + ':' + res.minutes();
  // return res.humanize();
}

calc_tot_dur();

Notice how much less you have to write? It also has the benefit that you can humanize the output, so instead of '00:30' it would say '30 minutes'.

gurvinder372 · Accepted Answer · 2016-04-25 11:14:16Z

you need to convert to number before adding

var total_durs = ['00:30', '01:30', '03:00', '04:30'];
var total = 0;
total_durs.forEach(function(val){
  var times = val.split(":");
  var num = parseInt(times[0],10) + parseInt(times[1],10)/60;
  total += num;
});

Now convert total to the time format (hh:mm)

var numstring = String(total).split(".");
var display = ("0" + String(numstring[0])).slice(-2) + ":" + String(numstring[1]*6);

DEMO

    var total_durs = ['00:30', '01:30', '03:00', '04:30'];
    var total = 0;
    total_durs.forEach(function(val){
      var times = val.split(":");
      var num = parseInt(times[0],10) + parseInt(times[1],10)/60;
      total += num;
    });


    var numstring = String(total).split(".");
    var display = ("0" + String(numstring[0])).slice(-2) + ":" + String(numstring[1]*6);

alert(display);

Redu · Accepted Answer · 2016-04-25 11:28:30Z

1

A simple one liner functional solution could be

var arr = ['00:30', '01:30', '03:00', '04:30'],
    tot = arr.map(e => e.split(":").map(e => e*1)).reduce((p,c) => [p[0] + c[0] + ~~((p[1]+c[1])/60), (p[1]+c[1])%60]);

document.write("<pre>" + tot[0] + ":" + tot[1] + "</pre>");

answered Apr 25, 2016 at 11:28

Redu

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