On Wed, Nov 12, 2014 at 6:34 PM, Tab Atkins Jr. <[email protected]> wrote: > On Wed, Nov 12, 2014 at 3:29 PM, James Long <[email protected]> wrote: >> On Wed, Nov 12, 2014 at 6:18 PM, Tab Atkins Jr. <[email protected]> wrote: >>> No, you're misunderstanding me, or the way that async stuff works. >>> >>> Calling an async function returns immediately. The called function >>> doesn't actually run until a later turn. If it throws, there's *no >>> way*, even theoretically, to throw that error at the call-site, >>> because the program counter is already well past that point. >>> >>> If you want the call-site to throw, then you need the callsite itself >>> to be in an async function, and you need to use the "await" >>> expression, which pauses execution of the caller until the callee's >>> returned promise settles. At that point you can throw the rejection >>> value, or return the fulfillment value. >> >> Trust me in that I've done a lot of async coding and I understand well >> how it works. The thing I may not understand fully is the current >> async/await spec. >> >> The difference is what happens with `await`, does it throw or does it >> automatically put the error on the promise returned from the async >> function. I'm essentially saying it should throw by default and you >> need to manually forward it. That's all. It doesn't really break >> anything. > > Something's still going wrong in your understanding here. "await" > *receives* a promise. It doesn't return one. It either returns the > fulfillment value or throws the rejection value. The question you're > asking doesn't make sense. > > ~TJ
`await` is *always* inside an `async` function so there's always a promise created for that function which is waiting for it to be done executing. That's the one I'm talking about. _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
