Function exception_to_promise

pub(crate) unsafe fn exception_to_promise(
    cx: *mut JSContext,
    rval: MutableHandle<Value>,
    _can_gc: CanGc,
) -> bool

Coverts exception to promise rejection

https://searchfox.org/mozilla-central/rev/b220e40ff2ee3d10ce68e07d8a8a577d5558e2a2/dom/bindings/BindingUtils.cpp#3315

Safety

cx must point to a valid, non-null JSContext.