Chrome is logging [Violation] errors in verbose console mode

[etpinard]

First reported https://community.plot.ly/t/violation-at-console/4518/7

To see it, open up https://codepen.io/etpinard/pen/ZyLQYy and turn on Verbose mode

The error message points to this line in dragbox.js.

[Violation] Added non-passive event listener to a scroll-blocking 'wheel' event. 
Consider marking event handler as 'passive' to make the page more responsive.

Observed in Chrome 59 and 58.

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Anyone know what this is about?

[rreusser]

I got the sense maybe they just added this to escalate the awareness of this general issue. I think it has to do with whether scrolling bubbles up to the window and then executes the callback or whether it executes the callback and then bubbles up to the window. Presumably it's more expensive UI-responsiveness-wise to block scrolling on your custom callback. Or something. See: https://developers.google.com/web/updates/2016/06/passive-event-listeners

[etpinard]

Related to #1240

[rreusser]

Let's see… this is a pretty good description of how to detect and apply it: https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md

[etpinard]

cc @dfcreative , which might know what this is about.

[efaden]

Did this ever get fixed...? My events are crashing when I try to perform some logic... I just get TONS of events.

[etpinard]

@dfcreative you're going for this?

[brian428]

Any thoughts on getting this fixed? We're showing multiple charts on the screen at once and these non-passive listener violations are flooding the console.

FYI, doing this is explained in detail at: https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md

[etpinard]

Unfortunately, this ticket fell off our short-term priority list. We'll gladly accept PRs from whoever is comfortable for the specs mentioned above.

In the meantime, the only workaround I can propose is to turn off Chrome's verbose logging level.

[etpinard]

Interesting report in https://community.plot.ly/t/scrollzoom-doesnt-work-in-chrome/7356 that might be related to this ticket.

[dy]

I am not sure we can fix that. In both cases where we attach event listener (scrollZoom and touch panning), we need it to block screen scrolling, therefore we cannot make it passive. In fact, the scenario of panning/zooming is explicitly explained here.
I'd suggest closing this.

[etpinard]

Ok. We can't just close this as clearly some people are finding this annoying.

I wonder if there's a way to turn off the those console warning without altering the functionality.

[dy]

#2251 fixes that, although exposes event listener on DOM node.