Timeline callbacks

Execute functions at specific points during a timeline playback.
Timeline callbacks functions are defined directly in the createTimeline() parameters Object.

createTimeline({
  defaults: {
    ease: 'out(3)',
    duration: 500,
  },
  loop: 3,
  alternate: true,
  autoplay: false,
┌─────────────────────┐
│ onBegin: () => {},  │
│ onLoop: () => {},   ├─ Callbacks
│ onUpdate: () => {}, │
└─────────────────────┘
});