Not working with iOS 11.3 Mobile Safari

It looks like the workaround

window.addEventListener( 'touchmove', function() {});

doesn’t work anymore with iOS 11.3 Mobile Safari. Is there a new workaround? 😅 It looks like that the same issue applies to Chrome on iOS as well.

[reppners]

Turns out the same workaround still applies but because Safari on iOS 11.3 enables passive event listener support it defaults to passive: true for event listeners on document level.

The fix is simple:

window.addEventListener('touchmove', function () { }, {passive: false})

But this puts the burden of feature detection of passive event listeners on the polyfill user. Maybe I should put this into another augmentation module so people who need to support Safari just import and apply a single makeItWorkOnSafari() function…

[reppners]

I don’t actually understand the workaround but is there anything that I have to worry/think about when using this? The “burden” you’ve mentioned, I don’t understand what you mean by that. I guess I would have to read up on passive event listeners and their feature detection. 😅

If you need to support older browsers (e.g. previous Safari) the third parameter on document.addEventListener() would be interpreted either as capture parameter or something else unintended happens.

To correctly apply the different workarounds you now have to check for passive event listener support and act accordingly

if(supportsPassive) {
  window.addEventListener('touchmove', function () { }, {passive: false});
}
else {
  window.addEventListener( 'touchmove', function() { });
}