Now that I think about it, this could also be done by adding a data attribute to every post with its root id and making a css selector that hides the root ids the user has blocked (the way notificationblock does it).

I don't think it really matters which way one does it. This way would perform slightly better when blocking or unblocking a post, I guess (no need to touch every post with classList.add/remove), but does it matter?

Now that I think about it, this could also be done by adding a data attribute to every post with its root id and making a css selector that hides the root ids the user has blocked (the way notificationblock does it).

I like this idea, I think it could really cut down on how many times the DOM is touched.

Also it seems like there's an awful lot of processing going on in checking and adding/removing classes that may or may not already be there for every single post on the dashboard.

Yep. Of course, it presumably makes the CSS engine have to do more work, which has to be done a lot more often then blocking/unblocking a post, which is done, you know, basically never :D But I'm constantly surprised at how unreasonably fast CSS layout engines seem to be.

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