Polymer + Cordova + PhoneGap + iOS = Very Laggy / Slow?

[wes]

I'm sorry this isn't necessarily a specific bug, but it is something I am noticing as developing an app in Polymer to be deployed as an app via PhoneGap. I have seen it take nearly 30 seconds to render a list of a 100 items. On a browser, its nearly instant.

When using certain things like:

<core-list id="list" data="{{data}}">
        <template>
            <div>stuff</div>
        </template>
</core-list>

[ebidel]

There are a lot of variables at play here!

What version of iOS? It's important to note that iOS will be running the polyfills (which are inherently slower than the native APIs) and all run JS. To compound the problem, you'll feel another major performance hit running that app inside a UIWebview. That's because Nitro JIT JS engine isn't available outside of Mobile Safari. This can account for a ~3-4x perf hit. So in iOS7, you're running js polyfills, slowly.

In iOS8, the new WKWebView runs JS as fast as mobile Safari

Not saying this helps you very much, but it's important to highlight.

[wes]

I was able to simplify my elements, and this seemed to help.. One of the biggest things was not using core-list and moving to something like

template repeat="{{item in items}}"

It dramatically improved the rendering time, I hope it helps someone. Thanks Eric for your help on this.

[ebidel]

Thanks. That's important info. @kevinpschaaf has been doing a lot of work on core-list. Were you using the 0.4.1 release or what's in master?

Reopening for now.

[wes]

Using master version, just installed using bower.

Thanks