Dot notation for types

[gustavopch]

type Bar = Foo.bar
type Bar = Foo!.bar
type Bar = Foo?.bar
type Bar = Foo?.bar ?? number
↓↓↓
type Bar = Foo['bar']
type Bar = NonNullable<Foo>['bar']
type Bar = NonNullable<Foo>['bar'] | undefined
type Bar = NonNullable<Foo>['bar'] | number

[STRd6]

I like it!

[orenelbaum]

I think that it breaks namespaces?

[edemaine]

Ideally we could detect that Foo is a namespace, but I'm afraid that requires compile-time type understanding. 😢

[orenelbaum]

Yeah I think that it's probably not practical

[STRd6]

We could add configuration based namespace whitelists for each popular library... but that would be a ton of work. I do think this is a good idea for the longer term and eventually there are things we'd like to do that require more advanced compile-time type/file processing. It's probably worth exploring (at least as an experimental option) to see what the practical complications are.

[orenelbaum]

Personally I don't use type indexing a lot so it seems to me like it's probably not worth the complexity. But maybe you guys are using type indexing more than me.

[STRd6]

If this does end up being generally impractical we can see about extending type destructuring to cover the same use cases.