No, it doesn't make any sense. Do you not see the impossibility of this? If you have a promise `a`:
You call `b = a.then(one).finally(done)` `b` is a promise. You can't have the thread waiting forever for every possible descendent to be added before executing the `done` function. There may even be none. On Fri, Sep 7, 2018, 13:27 Jon Ronnenberg <[email protected]> wrote: > I'm suggesting that finally is the last function to be executed. So > the chain is, then().then().then().catch().finally(), regardless of at > what time then or catch is added to the Promise chain. > Like try->catch->finally with a callback but without a callback. Does > it make sense? > On Fri, Sep 7, 2018 at 9:24 PM Peter Jaszkowiak <[email protected]> > wrote: > > > > There are plenty of ways of doing what you need without changing the > behavior of finally. Are you suggesting that calling finally make it so any > other then or catch call just not execute? And are you also suggesting that > this should climb up the chain of promises? > > > > On Fri, Sep 7, 2018, 13:16 Jon Ronnenberg <[email protected]> > wrote: > >> > >> I know I am late to the game and that Promise.prototype.finally is > already in stage 4 but(!). > >> > >> It's just not very useful to have a final function when it's not the > final function to run. If it's suppose to be for cleanup, then the current > implementation is seriously lacking usefulness. > >> > >> Consider the following example: > >> > >> <audio > >> class="i-am-the-element" > >> autoplay="autoplay" > >> controls="controls"> > >> <source type="audio/mp3" src="http:\/\/play.dogmazic.net > \/play\/index.php?type=song&oid=22951&uid=-1&name=Black%20poetry%20-%20Aime-.mp3"> > >> </audio> > >> <script> > >> class Demo { > >> constructor (element) { > >> this.node = element > >> } > >> destroy () { > >> return new Promise(resolve => { > >> // do something or nothing > >> resolve() > >> }).finally(() => { > >> // schedule for DOM removal > >> this.node = null > >> }) > >> } > >> } > >> > >> const demo = new Demo(document.querySelector('.i-am-the-element')) > >> > >> setTimeout(() => { > >> demo.destroy().then(() => { > >> // will throw an error because finally was run before > >> demo.node.pause() > >> }).catch(console.error) > >> }, 3000) > >> </script> > >> > >> One grand idea about promises is to delegate and compose asynchronous > functions, but the current implementation can not be used to for code > delegation. > >> > >> From the top of my head the only way to have consumer code, tap into > an execution process is to use callbacks which is what Promises were > suppose to help alleviate. > >> > >> <audio > >> class="i-am-the-element" > >> autoplay="autoplay" > >> controls="controls"> > >> <source type="audio/mp3" src="http:\/\/play.dogmazic.net > \/play\/index.php?type=song&oid=22951&uid=-1&name=Black%20poetry%20-%20Aime-.mp3"> > >> </audio> > >> <script> > >> class Demo { > >> constructor (element) { > >> this.node = element > >> } > >> destroy (callback) { > >> // do something or nothing > >> try { > >> callback() > >> } finally { > >> // schedule for DOM removal > >> this.node = null > >> } > >> } > >> } > >> > >> const demo = new Demo(document.querySelector('.i-am-the-element')) > >> > >> setTimeout(() => { > >> demo.destroy(() => { > >> demo.node.pause() > >> }) > >> }, 3000) > >> </script> > >> > >> If at all possible, please amend to the spec before it's too late! ... > or just drop it. > >> > >> My current use-case is that I work with PSPDFKit and can not get DOM > access but rather schedule removal of DOM nodes via their API, but I can > pause audio/video - just not using Promise.prototype.finally as it is > currently envisioned. > >> > >> Regards, Jon > >> > >> PS. Tested in Firefox 63.0b3 and Safari 11.1.2 > >> Here is a polyfill if you need: > https://cdn.polyfill.io/v2/polyfill.minify.js?features=Promise.prototype.finally&flags=gated > >> > >> _______________________________________________ > >> es-discuss mailing list > >> [email protected] > >> https://mail.mozilla.org/listinfo/es-discuss >
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