How to clear localStorage after logout user with rails?

Question

I have ROR application and i added countdown timer to it . The timer count from 15 to zero then disappear. What i'm doing is to prevent count again on refresh page , so , i stored start value in localStorage. But i need to reset the value when user log out and start count again when login again, here is my code:

function startTimer(duration, display) {
  var start = localStorage.getItem("start"),
  diff,
  minutes,
  seconds;
  var shown = false;

  if (start === null) {
    start = Date.now();
    localStorage.setItem("start", start);
  }
  function timer() {
    diff = duration - (((Date.now() - start) / 1000) | 0);

    minutes = (diff / 60) | 0;
    seconds = (diff % 60) | 0;
    minutes = minutes < 10 ? "0" + minutes : minutes;
    seconds = seconds < 10 ? "0" + seconds : seconds;
    display.textContent = minutes + ":" + seconds;
    if (diff <= 0) {
      start = 0;
      $('#testDiv').hide();
      if (shown == false){
        $('#congModal').modal('show'); 
        shown = true; 
      }
    }
  }

  timer();
  setInterval(timer, 1000);
}

window.onload = function () {
    var fifteenMinutes = 60 * 15,
        display = document.querySelector('#time');
    startTimer(fifteenMinutes, display);

};

and on view i have:

`%li.list-inline-item.g-mx-10--xl.g-font-size-16
              #testDiv{"data-value" => "show"}
                %span= "#{t('layouts.navbar.countdown.next_reward_in')}" 
                %span#time 15:00
                = "#{t('layouts.navbar.countdown.minutes')}"
              %i{"data-target" => "#congModal", "data-toggle" => "modal"}  `

Answer 1

This solved the problem!

on js file:

`function cleanUp(){
  localStorage.removeItem('start')
}`

on view:

%a{ "data-method" => "delete", href: destroy_user_session_path, onclick: "cleanUp();"}