Don't use native Object.observe for DOM objects' IDL properties about observe-js

[ebidel]

/sub

[rafaelw]

There is currently no plan to do that, and you've hit on the best example of why: offsetWidth is never directly stored, it must be computed. Accessing offsetWidth can be extremely expensive, forcing a browser layout. Allowing it to be observed would essentially be a giant go-slow button on the browser. Observing via the polyfill's approach of dirty-checking is just as bad. Basically, don't do this.

[stevehansen]

Too bad, I was hoping we finally had a method to handle a size changed event.
We need this in our application so we are forced to poll offsetWidth/offsetHeight regularly.

[stevehansen]

I used the following workaround for people who have the same problem as me.

http://www.backalleycoder.com/2013/03/18/cross-browser-event-based-element-resize-detection/

Works perfectly, cross platform and doesn't require a constant polling loop.

[rajsite]

There is a packaged version of the backalleycoder <object type=""text/html"> hack: https://github.com/KyleAMathews/element-resize-event

Not sure how far this proof-of-concept polyfill is going, but it has "CSS Element Queries" with a polyfill using scroll event hacks (the js for the polyfill might be reusable): https://github.com/marcj/css-element-queries

Polymer has an implementation that appears to avoid hacks by instead requiring all elements to communicate resize changes explicitly (appears to be the case but haven't looked through it completely): https://github.com/Polymer/core-resizable