Typescript: importing internal namespace

Question

I'm using a JS module, with typings from Definitely Typed, that has this structure:

declare namespace Foo {
  interface Bar {}
}

declare module "abc" {
    function f(): Foo.Bar

    namespace f {
    }

    export = f;
}

How can I import the Bar interface from "abc"?

Unfortunate you can't. The typings is not defined correctly to expose that. — unional
– unional, Commented Jul 13, 2018 at 15:46
You can't import what's not exported. The intent of that typing probably is to expose Foo as global object, along with "abc" module, and the only thing you can import from "abc" is f. — artem
– artem, Commented Jul 13, 2018 at 15:47

kingdaro · Accepted Answer · 2018-07-13 18:18:44Z

1

When something isn't explicitly exported, chances are, the author of the typings intends for you to not use the type.

...That being said, there technically is a way to get to it. TypeScript added a ReturnType type in 2.9 along with conditional types, which allows you to get the return type of a function. Here, you'd use it like this:

import f from 'abc'

type Bar = ReturnType<typeof f>

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answered Jul 13, 2018 at 18:18

kingdaro

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1 Comment

salezica Over a year ago

This is exactly what I needed. Thanks!

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