4 ms·

Wouldn't adding a way to block on an async function make javascript colorless? No one would want that though right? Like in what context would you even have a

• shadowgovt 2y ago
  You got the meat of the situation in these four sentences. Yes, mitigating the color issue in JavaScript is as "trivial" as allowing the `await` keyword inside non-`async` functions. And what that would mean more-or-less makes sense: the runtime sleeps the active execution thread and resumes it if and when something else in the runtime satisfies the await. But then you can't know, as the caller, whether any function has "sometimes this function just never returns" semantics without inspecting the whole call chain of every function you call (an arguably impossible task), and that's worse. Especially because the dominant use-case for JavaScript is browsers, where just blocking the UI thread forever is extremely bad. The fact `await` can only show up in a function declared `async` is a feature, not a bug---it saves the developer from a type of hell where they can't know, in the general case, if a function never returns.
  • dragonwriter 2y ago
    > But then you can't know, as the caller, whether any function has "sometimes this function just never returns" semantics without inspecting the whole call chain of every function you call (an arguably impossible task), and that's worse. You have exactly as much guarantee of this with async functions as with sync ones, though, but if there is a reason to worry about an async function where it is being called from a sync function and you need to provide a better guarantee, Promise.race() it with a timeout and...problem solved.