if (!localStorage.getItem('badValue')) {
  localStorage.setItem('badValue', Math.random());
}

var payload = localStorage.getItem('badValue'); // Using sync trigger.

setTimeout(function() {
  trigger(localStorage.getItem('badValue')); // Using the async trigger.

  // Clean up the localStorage to avoid causing side-effect on subsequent tests.
  localStorage.clear();
}, 10);
var div = document.createElement('div');
document.documentElement.appendChild(div);

// Sync trigger.
div.innerHTML = payload;

// Async trigger.
function trigger(payload) {
  div.innerHTML = payload;
};