alt Hacker NewsThe discussion around async await always focuses on asynchronous use-cases, but I see the biggest benefits when writing synchronous code. In JS, not having await in front of a statement means that nothing will interfere with your computation. This simplifies access to shared state without race conditions.
The other advantage is a rough classification in the type system. Not marking a function as async means that the author believes it can be run in a reasonable amount of time and is safe to run eg. on a UI main thread. In that sense, the propagation through the call hierarchy is a feature, not a bug.
I can see that maintaining multiple versions of a function is annoying for library authors, but on the other hand, functions like fs.readSync shouldn’t even exist. Other code could be running on this thread, so it's not acceptable to just freeze it arbitrarily.
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> This simplifies access to shared state without race conditions
But in ordinary JS there just can't be a race condition, everything is single threaded.
Maybe I am missing something. But the function coloring problem is basically the tension that async can dominate call hierarchies and the sync code in between looses it's beneficial properties to a degree. It's at least awkward to design a system that smoothly tries to blend sync that executes fast and async code that actually requires it.
Saying that fs.readSync shouldn't exist is really weird. Not all code written benefits from async nor even requires it. Running single threaded, sync programs is totally valid.