Optional arguments in Web IDL must be trailing arguments

[foolip]

https://wicg.github.io/animation-worklet/#creating-worklet-animation says:

[Constructor (DOMString animatorName,
              optional (AnimationEffectReadOnly or array)? effects = null,
              AnimationTimeline? timeline,
              optional WorkletAnimationOptions)]
interface WorkletAnimation : Animation {
        readonly attribute DOMString animatorName;
};

The 2nd and 4th arugment are optional, that doesn't work because the 3rd is not. Not clear if only the 4th should be optional, or 2-4 all optional.

[foolip]

Also note that optional WorkletAnimationOptions is missing an argument name.