News for hackers. Stuff that matters.
Re:Show HN: SentinelJS – Detect new DOM nodes using CSS sele... by myhf on Monday September 18, 2017 @05:23AM (#15274424)
There is some discussion about the motivation here:

http://www.backalleycoder.com/2012/04/25/i-want-a-damnodeins...

Re:Show HN: SentinelJS – Detect new DOM nodes using CSS sele... by atmin on Monday September 18, 2017 @05:50AM (#15274527)
And implementation by the same author: https://github.com/csuwildcat/SelectorListener
Re:Show HN: SentinelJS – Detect new DOM nodes using CSS sele... by ry_ry on Monday September 18, 2017 @05:35AM (#15274468)
Oh nice, thanks.

I'd actually completely forgotten about mutation observers too - they'd got mentally filed away under "browser vendors are why we can't have nice things".