fix doesn't work on iOS8 Safari

[krmbn0576]

In iOS8 Safari, performance isn't defined so TypeError may always be happened. I changed SceneManager._getTimeInMs simply returns undefined because it's no used in MobileSafari.

[ghost]

IMO It's not robust code. (ex. only iOS8 have no performance.now() ? )

It works, but You had better polyfill it.

[krmbn0576]

Of course it would be better to implement polyfill because SceneManager._getTimeInMs should have a responsibility for returning time on any device. But as a matter of fact, performance isn't defined only on iOS8 (See Can I use http://caniuse.com/#feat=high-resolution-time) and it's not used effectively on MobileSafari, so polyfill is overkill.

[ghost]

it's not used effectively on MobileSafari

No matter how to be used, Your Implementation breaks _getTimeInMs's semantics.

And Intention is not fully written. To understand the code, the reader must know all of browser's implementation.

Check existence of performance. It's good way to detect browser's feature.

[krmbn0576]

I still have a few suggestions because it is strange to write a polyfill that is not used at all at the moment.

• rename _getTimeInMs to_getTimeInMsWithoutMobileSafari
• add comment "this method can't be used in MobileSafari"

If neither is accepted, I'll give up and write polyfill. 😇

[ghost]

Simply, why not write ponyfill(not polyfill)? Like this.

if(window.performance) return performance.now();
else Date.now() - this._startTime;

Thinking about your suggestion, Not to modify _getTimeInMs. You'd better guard SceneManager: 31.

I think your suggetion means 'It's caller's prolbem'. It's clear intention, more preferable.

[krmbn0576]

OK, I finally rename _getTimeInMs to _getTimeInMsWithoutMobileSafari, and guard SceneManager: 31.