ReferenceError: TouchEvent is not defined

[paulkaplan]

TouchEvent is not always defined. Reported via Sentry. Doesn't seem to be a crashing error.

ReferenceError: TouchEvent is not defined
  at value (/lib.min.js:35:75460)
  at l (/lib.min.js:1:8318)

[towerofnix]

Going to quote my (duplicate-of-this) issue:

The "bad" line follows:

https://github.com/LLK/scratch-gui/blob/fc388b63c89559c4f25d069db84b49912b7a77fc/src/containers/stage.jsx#L203

Any non-left click makes the second condition, e instanceof TouchEvent, run. According to the compatibility section for TouchEvent, it looks like TouchEvent is defined only on Windows systems. Yikes!

[AmazingMech2418]

@towerofnix Browsers define the JavaScript functions, not the system.

[towerofnix]

@amazinigmech2418 Sure, but the browser can choose to define functions according to whatever system you're on. It seems silly to me to do that, but apparently Firefox does, per my link.

[2] As of Gecko 52.0, touch events support has been fixed and reenabled in Windows desktop platforms.

[AmazingMech2418]

@towerofnix That says that Windows can now use it. The touch events need to be processed by the browser from the actual event in the hardware. They just updated the event reader.

[regcole]

@paulkaplan @towerofnix @amazinigmech2418

To get this working (on FF at least)
change the line to

   if (e.button === 0 || window.TouchEvent && e instanceof TouchEvent) {