Hi Michael, I know a lot of folks are out on vacation so you may not get a quick authoritative answer. So here's a semi-quick, semi-authoritative answer.
Based on a discussion earlier this week with Steve and Kevin, I believe that this is now the expected behavior of Polymer.dom.flush(), and I'm planning on adding it to the documentation. Specifically, this feature was added in 1.0.8 in the following PR: https://github.com/Polymer/polymer/pull/2090 The feature is described in the PR, rather than being a side-effect of an unrelated change. Hope this semi-answer is semi-helpful, Arthur On Wed, Dec 16, 2015 at 12:03 AM, Michael Giuffrida <[email protected]> wrote: > > In general, calling `Polymer.dom.flush` provides a guarantee that these > tasks complete synchronously. > > sorry to dig up an old thread, but I was poking around in Polymer 1.0.4 > today and discovered that `Polymer.dom.flush` didn't guarantee > `dom-if` template rendering after changing the `if` property. Instead, > Polymer.Async > was necessary to ensure the `if` took effect > <http://jsfiddle.net/mnqpcqqd/1/>. > > `Polymer.dom.flush` does seem to work in recent versions of Polymer, but > the fact that it was insufficient in a previous 1.0 release worries me. We > rely on this in tests to avoid excessive async functions. I just wanted to > clarify whether we can consider `Polymer.dom.flush` sufficient to stamp the > template nowadays, or if it's just an implementation detail that may revert > to 1.0.4 behavior at any time. > > On Mon, Jul 27, 2015 at 10:30 AM Steve Orvell <[email protected]> wrote: > >> For efficiency, Polymer queues dynamic changes that provoke Shady DOM >> distribution (changes that fill insertion points, e.g. <content>) and >> template rendering (e.g. `dom-if` and `dom-repeat`) and processes them at >> microtask timing. In addition, the Custom Elements polyfill processes >> dynamic dom changes (upgrading elements and calling attached/detached) at >> microtask timing. >> >> In general, calling `Polymer.dom.flush` provides a guarantee that these >> tasks complete synchronously. >> >> On Thu, Jul 16, 2015 at 7:25 PM, Michael Giuffrida < >> [email protected]> wrote: >> >>> It would be really nice if anyone could provide a more detailed answer >>> to this and similar questions: It's not clear what operations are supposed >>> to be synchronous or asynchronous (and when async operations are at task >>> level vs. microtask level), which affects tests but also some more >>> complicated UI logic. >>> >>> I started a thread last week which didn't get any responses. I would >>> appreciate even a simple "we make no guarantees" response if that's the >>> case, because it would help knowing how defensive our code should be. >>> >>> Michael >>> >>> On Thu, Jul 16, 2015 at 4:02 PM, 'Daniel Freedman' via Polymer < >>> [email protected]> wrote: >>> >>>> Generally you can get away with not using flush. >>>> >>>> You may still need flush for testing element lifecycle callbacks in >>>> polyfilled browsers, or measuring DOM, but I expect very few cornercases >>>> like that. >>>> >>>> On Thu, Jul 16, 2015 at 10:46 AM, <[email protected]> wrote: >>>> >>>>> With Polymer 1.0, observers are now evaluated synchronously. If I >>>>> have an element whose behavior is driven by observers on attributes, and >>>>> everything appears to work in synchronous tests, is there any reason to >>>>> call flush()? That is, is it necessary that I call it before/after each >>>>> test? >>>>> >>>>> Follow Polymer on Google+: plus.google.com/107187849809354688692 >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Polymer" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/polymer-dev/adc4db0a-459d-4abf-ab8f-6453dae62213%40googlegroups.com >>>>> <https://groups.google.com/d/msgid/polymer-dev/adc4db0a-459d-4abf-ab8f-6453dae62213%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> Follow Polymer on Google+: plus.google.com/107187849809354688692 >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "Polymer" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/polymer-dev/CAAUAVAhtWUNOMEw8Zm2Nq5JVA0Q4ihDEtgPJ4pDjRVqZHk1ENA%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/polymer-dev/CAAUAVAhtWUNOMEw8Zm2Nq5JVA0Q4ihDEtgPJ4pDjRVqZHk1ENA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> Follow Polymer on Google+: plus.google.com/107187849809354688692 >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "Polymer" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> >> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/polymer-dev/CACi5S_1DeF4B%2BkgPzwpW8rt%3DH1dw%2B2%3D1C_BbGqgdzuD5ZtPpQw%40mail.gmail.com >>> <https://groups.google.com/d/msgid/polymer-dev/CACi5S_1DeF4B%2BkgPzwpW8rt%3DH1dw%2B2%3D1C_BbGqgdzuD5ZtPpQw%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >> >> >>> For more options, visit https://groups.google.com/d/optout. >>> >> Follow Polymer on Google+: plus.google.com/107187849809354688692 > --- > You received this message because you are subscribed to the Google Groups > "Polymer" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/polymer-dev/CACi5S_2OG5_0DEBLdBUexZ%3DjY3UT-4x7hR8YQvr1SeQnkg5JBA%40mail.gmail.com > <https://groups.google.com/d/msgid/polymer-dev/CACi5S_2OG5_0DEBLdBUexZ%3DjY3UT-4x7hR8YQvr1SeQnkg5JBA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > Follow Polymer on Google+: plus.google.com/107187849809354688692 --- You received this message because you are subscribed to the Google Groups "Polymer" group. 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