Calling clock.clear() inside a callback function breaks the tick

[renatopp]

When you try to clear the clock inside a timeout or interval callback, the tick function fail:

TypeError: Cannot read property 'active' of undefined

Reproducing it:

const clock = new ClockTimer();

clock.setTimeout(() => {}, 0);
clock.setTimeout(() => {
  clock.clear();
}, 0);
clock.setTimeout(() => {}, 0);

clock.tick();