Should MutationObserver ensure HTML file nodes are run through it before they're injected in DOM?

[Zibi Braniecki]

I'm trying to use MutationObserver to do runtime localization of the nodes that are provided by an HTML file.

I register the mutation observer on document at it's readyState=loading and in result all nodes that are in HTML files are reported to my callback. That's cool.

Now, usually, firstPaint happen after this, so if I translate those nodes, all I see on firstPaint is a stable screen with properly translated nodes.

The order seems to be:

1) observer registered
2) nodes injected into DOM
3) observer's callback translates the nodes
4) firstPaint

But when I test this on a slow device (Keon) and on a rather complex app (Settings), every now and then I see a flash of untranslated content before the nodes are being translated by the mutation observer's callback.

It just seems that in those cases the order is:

1) observer registered
2) nodes injected into DOM
3) firstPaint
4) obsever's callback translates the nodes

Question: should mutationobserver's callback be run on those nodes before firstPaint?

Or

Question 2: should mutationobserver's callback be run on those nodes before they are injected into DOM?

Thanks,
zb.

[Jonas Sicking]

On Fri, Apr 18, 2014 at 3:29 PM, Zibi Braniecki
<zbigniew....@gmail.com> wrote:

> Question: should mutationobserver's callback be run on those nodes before firstPaint?

Yes

> Question 2: should mutationobserver's callback be run on those nodes before they are injected into DOM?

No. That would require them to fire synchronously and bring back a lot
of the problems that we had (and still have) with MutationEvents.

/ Jonas