Can you clarify what you mean for someone unfamiliar? If Closure Compiler is sticking around (and the linked issue is very clear that it will), what is it that ClojureScript needs to have a plan to remove?
So this is just the usual "Google kills projects lol" comment and not something based in any information about Closure Compiler specifically. Understood.
All of Google's JavaScript and TypeScript is compiled with Closure compiler. It's not going anywhere.
You're only relating the two because they share a name from being kind of sort of part of the same project 20 years ago. Closure library hasn't been used internally for a new code for a very long time.
I have a causeway (going with something different for variety) to sell you because you don’t take into account that the ClojureScript project can just fork because they have sufficient access to expertise (most projects don’t, but they do, partly because they’re big enough and partly because they’re very strong with computer science). You raise a good point but don’t allow for solutions to be presented and assume it’s a distaster scenario.
