Does `is not` equal to `isnt`

[bcho]

The code likes that:

x = 'foo' if y is not null else 'bar'

will generate this js code:

x = (y === !null) ? 'foo' : 'bar';

but actually what I want is:

x = (y !== null) ? 'foo' : 'bar';

And the second generated code is exactlly what isnt generated.

So, does is not not equal to isnt ?

[rzimmerman]

I agree this is confusing. "is not" should be equivalent to "isnt" (I'll work it in). "doesnt exist" works well for null checks at the moment.