Catch exceptions while assigning event.timeStamp

[briganti]

Summary

On some old browsers such as Safari mobile 9, Firefox 52 or Chrome mobile 58, trying to set a read-only property raises an exception TypeError: setting a property that has only a getter.

This has been fixed on the Zepto repository, in this PR. But since no release has been done, it's not available via Semver.

This PR applies the above patch to the versioned Zepto file.

[coveralls]

Coverage remained the same at 88.959% when pulling f7cf20e on briganti:zepto-event-timestamp into 906d8b7 on algolia:master.

[Haroenv]

This looks like a valid fix, thanks! Do you have a broken app, so we can confirm what behaviour exactly changed? Thanks!

[briganti]

I've more info about this error. On these old browsers, event.timeStamp is set incorrectly to 0 (instead of the Epoch time it was created). This is what I've got on FF 52:

This causes the following code:

https://github.com/algolia/autocomplete.js/blob/906d8b7fedfa9a203b7d05a2daeffdc190b5304c/zepto.js#L1080

to assign event.timeStamp to the current time. But there is one problem, event.timeStamp cannot be changed - it's a read-only property. Trying to do so will raise a TypeError exception.

I was struggling to reproduce this error on the playground page. Until I notice that the Zepto library is not using strict mode. That's why the TypeError exception does not appear in the console logs, it got ignored by the browser.

But in my app, autocomplete.js lib is part of a strict mode bundle.

Now, I can set the Zepto file in strict mode (that'll make the error shows up on the playground page), but that might cause some other exceptions to pop up. Wdyt @Haroenv