Now

Among other custom element-related DOM properties, like connectedCallback, disconnectedCallback, adoptedCallback, attributeChangedCallback, etc. there's also a static property called observedAttributes.

I realized this property is missing when mangling a Lit web component app. I added it to save anyone doing the same thing some trouble.

Additional

There are some other missing properties. Some of these released in stable Chrome on Feb 4, 2025, so it may be time to add them here as well.

1. moveBefore (Chrome 133, Firefox 144, Safari soon?)
2. connectedMoveCallback (Chrome 133, Firefox 144, Safari soon?)
3. Temporal (Chrome 144, Firefox 139, Safari soon?)
4. Temporal.Duration (Chrome 144, Firefox 139, Safari soon?)
5. Temporal.Instant (Chrome 144, Firefox 139, Safari soon?)
6. Temporal.Now (Chrome 144, Firefox 139, Safari soon?)
7. Temporal.PlainDate (Chrome 144, Firefox 139, Safari soon?)
8. Temporal.PlainDateTime (Chrome 144, Firefox 139, Safari soon?)
9. Temporal.PlainMonthDay (Chrome 144, Firefox 139, Safari soon?)
10. Temporal.PlainTime (Chrome 144, Firefox 139, Safari soon?)
11. Temporal.PlainYearMonth (Chrome 144, Firefox 139, Safari soon?)
12. Temporal.ZonedDateTime (Chrome 144, Firefox 139, Safari soon?)