Counter reset every time reset

Question

I have a contact day, hour, minute and second, from there I program for example: in 2 days (regressive), I would like when it zeroes start counting again, type 2 in 2 days, or 1 in 1, not to need every time Zera have to keep making date changes!
Follow the code:

var target_date = new Date("\n" + " October 15, 2019").getTime();
var dias, horas, minutos, segundos;
var regressiva = document.getElementById("regressiva");

setInterval(function() {

    var current_date = new Date().getTime();
    var segundos_f = (target_date - current_date) / 1000;

    dias = parseInt(segundos_f / 86400);
    segundos_f = segundos_f % 86400;

    horas = parseInt(segundos_f / 3600);
    segundos_f = segundos_f % 3600;

    minutos = parseInt(segundos_f / 60);
    segundos = parseInt(segundos_f % 60);


    document.getElementById('dia').innerHTML = dias;
    document.getElementById('hora').innerHTML = horas;
    document.getElementById('minuto').innerHTML = minutos;
    document.getElementById('segundo').innerHTML = segundos;


}, 1000);

Answer 1

Paulo, check that the timer has reached zero and then assign a new value to target_date. This way whenever the timer zeroes will be assigned a new timer of x days more:

// (...)
var segundos_f = (target_date - current_date) / 1000;
if (segundos_f <= 0) {
    const a = new Date();
    a.setDate(a.getDate() + 2 /* mais 2 dias, por exemplo */);
    target_date = a.getTime();
    return;
}
// (...)

Answer 2

Hello Paul I made an example, but, I did not test. But the logic I implemented is very simple:

1. I put the day on the date in the form of string template to make it easier to manipulate the counting days.

2. I removed the codes from inside the setInterval() and inserted within a function, more for the sake of readability.

3. I created a if within the function for when hours, minutes and seconds are zeros increment the date.

4. Also by insertion legibility 0 before the time, minutes and seconds less than 10.

var data = 15;
var target_date = new Date(`\n October ${data}, 2019`).getTime();
var dias, horas, minutos, segundos;
var regressiva = document.getElementById("regressiva");

setInterval(function() {
  Timer();
}, 1000);

function Timer() {
  var current_date = new Date().getTime();
  var segundos_f = (target_date - current_date) / 1000;

  dias = parseInt(segundos_f / 86400);
  segundos_f = segundos_f % 86400;

  horas = parseInt(segundos_f / 3600);
  segundos_f = segundos_f % 3600;

  minutos = parseInt(segundos_f / 60);
  segundos = parseInt(segundos_f % 60);

  document.getElementById('dia').innerHTML = dias;
  document.getElementById('hora').innerHTML = horas < 10 ? `0${horas}` : `${horas}`;
  document.getElementById('minuto').innerHTML = minutos < 10 ? `0${minutos}` : `${minutos}`;
  document.getElementById('segundo').innerHTML = segundos < 10 ? `0${segundos}` : `${segundos}`;
  
  if(horas == 0 && minutos == 0 && segundos == 0) {
    data = data + 2;
  }
}

<b>Dias</b> <span id="dia"></span> -
<b>Tempo</b> <span id="hora"></span>:<span id="minuto"></span>:<span id="segundo"></span>