null vs undefined handling about jexl HOT 3 OPEN

Hi Winston! I apologize for responding so late on this. I've been chewing on it ever since you posted it, and I keep arriving at this making the most sense as a constructor option that allows the programmer to enable JS-native functionality on throwing when a property of undefined is accessed.

I'm not in love the idea of using null vs undefined, because ultimately either of those things could be legitimate values inside the context. If Jexl threw an exception, that would make the difference quite clear -- at the expense of the programmer needing to catch the error if they enable this mode.

What do you think?

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Hi! Yes, getting an exception would be good, especially if that exception can contain more information. If my expression was "foo.bar[12].gates.yellow", it'd be nice if the exception could indicate where exactly the undefined was.

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Hi Tom, I'm having the same issue when comparing "null == undefined" or "null != undefined", both return back as undefined and will be true when comparing equality, when making a custom operator with using typeof undefined or typeof null both return a string "undefined", but typeof null should actually return a string "object" here instead of "undefined". This should resolve the issue.

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