With optional it does not work with null

[unional]

No description provided.

[blakeembrey]

Using null is a TypeScript nightly only feature and breaks everyone using a stable release.

[unional]

Yeah, any alternative solution?

[blakeembrey]

Not that I know of, I've worked around it in other places by using void, but that doesn't allow null - just undefined.

[louy]

AFAIK null = any > void. So it should work.

[blakeembrey]

@louy Sorry, I didn't understand that notation?

[louy]

Sorry. I meant any contains void. Couldn't find the symbol ⊃ on my keyboard.

In TS 1.8 null has type any, meaning that if you pass null as void it should work fine.

For example:

function test(x: void) {}
test(null); // <-- no errors

[louy]

I've just realised that the problem @unional is having is with TS nightly as null should work fine with the current typing (there wasn't much context for this PR).

I don't think we can do anything about this for now to make it work with both versions. Anyway non-nullable types are a version 2.0 feature so I think we don't have to worry about them for now.

[unional]

@louy yeah, notice that it is working fine when I actually open this project and run the tests.

Wouldn't it be a backward compatibility issue with nullable type? Seems like this will break a lot of typings when TS 2.0 is released.

[blakeembrey]

Absolutely, it kind of does - but that's what a 2.0 is for, I suppose. I've been having a pretty good run using strictNullChecks and the nightlies for around 3 months on the current project. The only thing I've changed is typings where I used void (which is really the only backward-compatible way to partially fix this).