Is == faster than checking null and undefined separately?

If we are going to do this, might as well check !obj; it's clearer of the intention.

But !obj will give different error messages with Boolean values, as false value will enter this block.

@cjihrig Yes. If you look at the IR produced by Hydrogen it has a single instruction for "check-null-or-undefined".

@Fishrock123 fromObject() is a catch-all for other values not parsed elsewhere. This is an explicit check for the two following:

> new Buffer(null)
TypeError: Cannot read property 'buffer' of null

> new Buffer()
TypeError: Cannot read property 'buffer' of undefined

Everything else will fall through and hit the exception at the bottom of the function.

Maybe include an explicit test for null too, just in case the code changes in the future.

+1 to that if we're going with == null

good call