Awhile back I did my best to summarize some of the previous es-discuss threads on a related GitHub thread: https://github.com/iojs/io.js/issues/11#issuecomment-65971175
Please see the immediately following comment as well for some clarification on how Bluebird surfaces unhandled rejections. On Tue, Jan 13, 2015 at 11:27 AM, Jeff Morrison <[email protected]> wrote: > You might try reading through some of the previous threads that talk > about the trickiness of surfacing promise errors in the general case. > > Unfortunately these threads usually devolve into an endless thread of > discussion and debate that become next to impossible to actually read > through later without several hours of spare time and a bottle of > whiskey... But here's a recent one that's not *too* long and kind of talks > about a couple of ideas: > > https://esdiscuss.org/topic/async-await-improvements (long, but talks > about a couple potential/proposed solutions) > > -Jeff > > > On 1/13/15 7:44 AM, Marius Gundersen wrote: > > A `promise.done()` method that throws if it receives a rejected promise > has been discussed, but the consensus seems to be that browsers instead > should report on rejected unhandled promises that are garbage collected. > This is already implemented in Firefox (at least in the DevTools edition), > where the following code will end up with an error in the console: > > ```js > var p = new Promise(function(){throw new Error("oh noes");}) > p = null; > ``` > > Since there is no way to handle the thrown error outside the promise (the > exception is thrown after the function returns) there isn't any reason for > the exception to travel up the stack. Either the exception must be handled > as a rejected promise or it must be handled in something like > `window.onerror`. > > Marius Gundersen > > On Tue, Jan 13, 2015 at 12:35 PM, Boopathi Rajaa <[email protected]> > wrote: > >> ``` >> Promise >> .resolve() >> .then(function(){ >> throw new Error('asdf'); >> }); >> ``` >> >> Bluebird: (errors thrown - Good) >> http://jsbin.com/kahuzi/1/edit?html,js,console >> >> native ES6:(errors not thrown) >> http://jsbin.com/qivobibowa/3/edit?html,js,console >> >> Shouldn't all Uncaught errors be thrown, instead of catching it inside >> the promise only ? For example, If I use Promise within a promise, the >> uncaught error in the inner Promise will never be exposed to the outside >> world and there is no way to bubble it up to the outside blocks. >> >> `.catch(function(err) { throw err; }) ` >> >> will also be caught and nothing would be thrown. >> >> - Boopathi >> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> >> > > > _______________________________________________ > es-discuss mailing > [email protected]https://mail.mozilla.org/listinfo/es-discuss > > > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > -- Jeremy Martin 661.312.3853 http://devsmash.com @jmar777
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