[0.8] - default property values are not set by the time observers are called #1364

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1. ebidel

   added

   0.8

   on Apr 2, 2015
2. sorvell commented on Apr 3, 2015

   

   sorvell

   on Apr 3, 2015

   Contributor

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   You cannot depend on the value of one property in the observer of another. Instead consider this:

   observers: {
     'key published': 'doStuff'
   }
   
3. ebidel commented on Apr 5, 2015

   

   ebidel

   on Apr 5, 2015

   ContributorAuthor

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   Thanks @sorvell. So is this the recommended pattern now? I also want to react to individual properties changing later on.

   @arthurevans I think we can be more precise in the section on observers. What's not clear:

   1. When does the callback get called? end of micro task?
   2. If any of the properties change, the callback gets called. People could think they all have to change.
4. sorvell commented on Apr 6, 2015

   

   sorvell

   on Apr 6, 2015

   Contributor

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   So is this
   https://github.com/Polymer/core-ajax/blob/0.8-preview/core-ajax.html#L308-L311 the
   recommended pattern now?

   Yes, but this is an area we're still refining so it may change slightly in
   the 0.9 timeframe.

   When does the callback get called? end of micro task?

   Yes

   If any of the properties change, the callback gets called. People could
   think they all have to change.

   Yes

   On Sun, Apr 5, 2015 at 9:40 AM, Eric Bidelman notifications@github.com
   wrote:

   Thanks @sorvell https://github.com/sorvell. So is this
   https://github.com/Polymer/core-ajax/blob/0.8-preview/core-ajax.html#L308-L311
   the recommended pattern now? I also want to react to individual properties
   changing later on.

   @arthurevans https://github.com/arthurevans I think we can be more
   precise in the section on observers
   https://www.polymer-project.org/0.8/docs/devguide/properties.html#observing-changes-to-multiple-properties.
   What's not clear:

   1. When does the callback get called? end of micro task?
   2. If any of the properties change, the callback gets called. People
      could think they all have to change.

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   Reply to this email directly or view it on GitHub
   #1364 (comment).
5. sorvell

   closed this as completedon May 22, 2015