Proposal: Consider introducing a shorthand syntax for nullable types

[MartinHaeusler]

Static analysis on "nullable" variables is a good thing. However, using this feature also requires to explicitly create union types with null for every variable and member that can in fact be null. So, for example to create a nullable (and undefineable) number member...

interface MyInterface {
  x: number | null | undefined
}

It is currently possible to use a shortcut for undefined:

interface MyInterface {
   x?: number | null
}

Note that the two interface definitions above are equivalent, but | null is always required.

However, for my taste, this is all way too verbose for something as common as a nullable type. I would like to propose the following:

interface MyInterface {
   x: number?
}

... where number? is the shorthand for number | null | undefined. This little tweak would save a lot of typing and improve general acceptance of strict null checking. This isn't a new idea. Languages like Ceylon use the same method and syntax.

[aluanhaddad]

See #7426 where a long and contentious debate has taken place.

[MartinHaeusler]

Thanks for the pointer, but the discussion in this ticket seems a bit... inconclusive to me? The other ticket is closed, but I can't see clearly what the upshot of the discussion was (without having read the entire thing).

[ahejlsberg]

Conclusion is here: #7426 (comment). Basically, there is no consensus on what T? should mean and therefore we don't have a shorthand notation.

[RyanCavanaugh]

See also #7488