Re: [polymer-dev] Dom-Repeat Render: What is it actually do ?
This section describes the use cases for render:
https://www.polymer-project.org/1.0/docs/devguide/templates#synchronous-renders
Most common use case is probably re-running the sort and/or filter
functions when an external piece of data changes. But there are a couple of
other uses, like unit testing.
Another example is in the iron-doc-viewer element that displays Polymer API
docs. It has a set of dom-repeats that render properties, methods, and
events. When you follow a direct link to an API page, like:
https://www.polymer-project.org/1.0/docs/api/dom-repeat#method-render
It needs to make sure those repeats are all rendered before it tries to
scroll to the chosen anchor. (It actually uses Polymer.dom.flush() in this
case, but it has the same effect, which ensuring that the templates have
rendered.)
So, in summary:
- It doesn't do anything to change the dom-repeat's view of the data. If
you want to notify the dom-repeat that some arbitrary data in your array
has changed, your best bet is to do a shallow clone of the array:
this.myArray
= this.myArray.slice();
- It does ensure that rendering is done by the time it returns, which
can be useful for unit testing, or scrolling to an element generated by the
dom-repeat.
- It forces the dom-repeat to re-run its sort and filter functions, even
if it doesn't appear that anything has changed.
Hope that helps.
Arthur
On Tue, Nov 1, 2016 at 5:44 AM, Quang Le wrote:
> Thank you
>
> I did know how to make the change as you suggested (if you look at my
> whole code)
> I just want more detail on what the *render *function actually does, in
> order to use it properly.
>
>
> On Tuesday, November 1, 2016 at 12:37:05 PM UTC+7, Karl Tiedt wrote:
>>
>> Because you are by passing the binding functionality of Polymer for
>> Objects and Arrays... Because Polymer does not use mutation observers due
>> to performance issues Objects and Arrays have to be notified of changes,
>> this is done by using this.set as described very clearly in the
>> documentation. The below method with the single line, is enough to get what
>> you expected.
>>
>> // call dom-repeat render
>> _renderDREmployees: function() {
>> this.set('employees.0.name',"RENDERED");
>> },
>>
>> -Karl Tiedt
>>
> Follow Polymer on Google+: plus.google.com/107187849809354688692
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Re: [polymer-dev] Dom-Repeat Render: What is it actually do ?
Thank you
I did know how to make the change as you suggested (if you look at my whole
code)
I just want more detail on what the *render *function actually does, in
order to use it properly.
On Tuesday, November 1, 2016 at 12:37:05 PM UTC+7, Karl Tiedt wrote:
>
> Because you are by passing the binding functionality of Polymer for
> Objects and Arrays... Because Polymer does not use mutation observers due
> to performance issues Objects and Arrays have to be notified of changes,
> this is done by using this.set as described very clearly in the
> documentation. The below method with the single line, is enough to get what
> you expected.
>
> // call dom-repeat render
> _renderDREmployees: function() {
> this.set('employees.0.name',"RENDERED");
> },
>
> -Karl Tiedt
>
Follow Polymer on Google+: plus.google.com/107187849809354688692
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Re: [polymer-dev] Dom-Repeat Render: What is it actually do ?
Because you are by passing the binding functionality of Polymer for Objects
and Arrays... Because Polymer does not use mutation observers due to
performance issues Objects and Arrays have to be notified of changes, this
is done by using this.set as described very clearly in the documentation.
The below method with the single line, is enough to get what you expected.
// call dom-repeat render
_renderDREmployees: function() {
this.set('employees.0.name',"RENDERED");
},
-Karl Tiedt
On Mon, Oct 31, 2016 at 7:34 PM, Quang Le wrote:
> I was fighting with a nested dom-repeat for the last 2 days.
> I somewhat now know how to re-render when sub-properties changed.
>
> But still don't understand the purpose of the render function.
> I changed the data binded to a dom-repeat, and call the render, but
> nothing happens.
>
> See here
> http://plnkr.co/edit/Y0P5vNxg46t5fX7gJFxU?p=preview
>
> Could somebody explain to me please?
>
> If you could take a look of my example, to see if I do it the right away.
> What could be other ways/proper way to re-render item inside a dom-repeat
> when the data that binded to it was changed outside.
>
> Thank you
>
>
>
> Follow Polymer on Google+: plus.google.com/107187849809354688692
> ---
> You received this message because you are subscribed to the Google Groups
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> msgid/polymer-dev/79cb695c-65cb-4794-80c4-292471cca595%40googlegroups.com
>
> .
> For more options, visit https://groups.google.com/d/optout.
>
Follow Polymer on Google+: plus.google.com/107187849809354688692
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[polymer-dev] Dom-Repeat Render: What is it actually do ?
I was fighting with a nested dom-repeat for the last 2 days. I somewhat now know how to re-render when sub-properties changed. But still don't understand the purpose of the render function. I changed the data binded to a dom-repeat, and call the render, but nothing happens. See here http://plnkr.co/edit/Y0P5vNxg46t5fX7gJFxU?p=preview Could somebody explain to me please? If you could take a look of my example, to see if I do it the right away. What could be other ways/proper way to re-render item inside a dom-repeat when the data that binded to it was changed outside. Thank you 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 polymer-dev+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/polymer-dev/79cb695c-65cb-4794-80c4-292471cca595%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
