Uncaught TypeError: Cannot read property 'pageX' of undefined

This error originates from the pointerMove event listener, initiating a call chain to setEventXY and getPageXY, where evidently the pointer is has been passed in as undefined.

Seen on Google Chrome and Chrome Mobile, running on WIndows 8.1, Android 4.4, Windows (version undefined) and Linux.

getPageXY should handle null pointer exceptions (no pun intended).

[taye]

I’ve pushed a thing to the stable branch to avoid PointerEvents in Chrome. If you’re using v1.2.*, updating to v1.2.8 should solve this issue when it’s related to PointerEvents.

[stevelove]

@taye I haven’t tried the unstable branch, but I can easily reproduce this issue in Chrome 55.0.2883.75 on http://interactjs.io/

Steps to reproduce:

1. Make sure your browser window is not maximized.
2. Open the Chrome Developer Tools console.
3. Visit http://interactjs.io/
4. Move your mouse off of, then back onto the browser window again.
5. Observe that each time your mouse moves onto the browser window, Uncaught TypeError: Cannot read property 'pageX' of undefined appears in the console.

Alternative reproduction: The error appears simply by moving your mouse onto the webpage from the browser chrome area (tabs, address bar, bookmarks, etc).