I think you mixed up "du jour" and "de jure" there.

It does suggest, however, both "de jure du jour" and "du jour de jure".

It may not come from an individual, but there is certainly an element of the JS community that seems to operate de jure. Frameworks are "the next hot thing" before they've hardly shipped a production site of any consequence, let alone shown the ability to improve things across a large array of sites, or had time for the negatives to be shaken out. Or a "next hot thing" ships one massive site like Facebook or something and it's the "next hot thing" before anybody can realize that they aren't Facebook and don't have three hundred dedicated front end developers themselves, and it's way less clear the NHT will work for two guys in a closet working on a startup.

Wouldn't that be de facto? De jure would mean there is some kind of law. I feel we have the opposite, quickly shifting de facto standards without any place to reference what is "correct" today.

I'm using de jure to contrast the de facto; I think frameworks are the "next big thing" before they're even fact. That Javascript Guy comes up to you, asks you what you're using, and then berates you for not using Hot New Thing, de jure-ing you into using it, or at least feeling bad for not using it.

Part of the way I've resisted being sucked into the JS vortex over the past few years is that I thoroughly reject the authoritative claims that I should be using X or Y, on the grounds that I don't particularly respect the technical judgment of the people making those claims. (And check that last clause carefully; all the Next Big Things are generally engineered pretty well, it's the advocates berating you for not keeping up to date that I'm dissing.)