Every other system I've ever worked with has the signature hash(bytes) => bytes, yet whatever committee designed the Subtle Crypto API decided that the browser version should return a promise. Why? I've looked around but I've never found any discussion on the motivation behind that.
async/await infecting all of my code, being unable to create a get myField() method that involves a hash calculation. It may be standard to do heavy lifting concurrently, but async hash functions are certainly not standard in any of the languages I've used (which is quite a few).
From browsing your other comments on this thread I understand that you are in a context where you can’t await, that you expect the invocation to take very little time, and that the library offers no complementary sync interface.
As far was I know you’re stuck in this case. I consider the stubborn refusal to add “resolve this promise synchronously right now” a major flaw in js.