allow type declarations inside objects

interface W<X, Y, Z> { x: X; y: Y; z: Z; }

function toModule<X, Y, Z>()  {
     type $W = W<X, Y, Z>;
     return {
        W: $W // <-- wish could do that
     };
}

const m = toModule<string, number, boolean>();
const w : m.W = { // <-- wish could do that
   x: '',
   y: 0,
   z: false
};

so namespace expressions, a la class expressions?

please allow either of the following:

either namespaces that can be parametrized with types and values Suggestion: Allow type and value parameters for modules #2625
or, which is mostly equivalent, allow types in the position of object properties like in the example above

here is a sample:

function toModule<X, Y, Z>()  {
     return namespace {
        export interface W { x: X; y: Y; z: Z; }
    }
}

const m = toModule<string, number, boolean>();
const w : m.W = { // <-- wish could do that
   x: '',
   y: 0,
   z: false
};

both approach has issues with the current implementations that assumes an expression can only be a value, and not a namespace. we will need a proposal for this one.

Workaround

This is the workaround that I have to use now:

interface W<X, Y, Z> { x: X; y: Y; z: Z; }

function toModule<X, Y, Z>()  {
     const $W : W<X, Y, Z>;
     return {
        W: $W
     };
}

const m = toModule<string, number, boolean>();
const w : typeof m.W = {
   x: '',
   y: 0,
   z: false
};

👍

Mohamed Hegazy (@mhegazy)

Mohamed Hegazy (@mhegazy)

here is a sample:

that would be super great

I am afraid that alone returning a namespace isn't enough. It needs to be also passed as an argument and taken as a parameter. In order to declare it it has to have a type. Do namespaces have a type per se? Doubt so. Anyway, I believe that the difference between namespaces and objects is a made up. It would be great to see namepaces unified with objects because to JavaScript they are the same.

closing in favor of #8358

Navigation Menu

Repository navigation

allow type declarations inside objects #8308

Workaround

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

allow type declarations inside objects #8308

Description

Activity

mhegazy commented on Apr 26, 2016

zpdDG4gta8XKpMCd commented on Apr 26, 2016

mhegazy commented on Apr 26, 2016

mhegazy commented on Apr 26, 2016

zpdDG4gta8XKpMCd commented on Apr 26, 2016

Workaround

aluanhaddad commented on Apr 26, 2016

zpdDG4gta8XKpMCd commented on Apr 26, 2016

zpdDG4gta8XKpMCd commented on Apr 28, 2016

zpdDG4gta8XKpMCd commented on Apr 28, 2016

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions