module declaration and conditional require

[farfromrefug]

Yesterday i was doing this which was working great:

declare module 'noble' {
    export type State = "unknown" | "resetting" | "unsupported" | "unauthorized" | "poweredOff" | "poweredOn";
    export var state: State

    export interface Peripheral {
        type: string
    }

    export interface Characteristic {
        subscribe(callback?: (error: string) => void): void;
    }
}
import * as noble from 'noble'

Now i need to transform import * as noble from 'noble' into:

let noble = require('noble');
if (/win/.test(process.platform)) {
    noble = require('noble-uwp');
}

Both require actually use the same declaration. However i can't find a way to tell typescript that noble is of 'type' noble(the module)

Is there any way to do this with typescript?

THanks

[ghost]

Try doing it without require().

import * as nobleA from "noble";
import * as nobleB from "noble-uwp";
const noble = /win/.test(process.platform) ? nobleB : nobleA;

[farfromrefug]

@andy-ms but the issue is that the import of "noble-uwp" wont work on macos as it is a windows module.
So i would need to do it within a try/catch.
But i can't do an import within a try/catch.

That's why i am looking at declaring the module and using it as a "type"

[blakeembrey]

@farfromrefug You can use imports for the type and then use the types-only, not the value (e.g. https://github.com/TypeStrong/ts-node/blob/b751a56e8a094d6905e47e4c96ab43a931bf4cb8/src/index.ts#L180). You might want to prefix noble with an _ or something to avoid accidentally using it though since there's no type-only imports with TypeScript.

import * as noble from 'noble'

const x: typeof noble = require('noble')

[mhegazy]

Full support for dynamic imports will come with import(..) statement support, see #14495 for more details.

[farfromrefug]

@blakeembrey i tried what you suggest by doing this:

declare module 'noble' {
    export type State = "unknown" | "resetting" | "unsupported" | "unauthorized" | "poweredOff" | "poweredOn";
    export var state: State

    export interface Peripheral {
        type: string
    }

    export interface Characteristic {
        subscribe(callback?: (error: string) => void): void;
    }
}
import * as _noble from 'noble';
let noble: typeof _noble = require('noble');
if (/win/.test(process.platform)) {
    noble = require('noble-uwp');
}

If i do noble. the autocompletation gives me access to the interfaces within the module
However when i do

interface Peripheral extends noble.Peripheral {
}

i get an error can't find namespace 'noble'
I think this is because noble is seen as a variable and not a module/namespace?
Is there a way around this?

@mhegazy thanks for the heads up. This will take quite some time i guesss?

[kitsonk]

It is targeted for 2.4 at the moment, which isn't forever in the future. Next major release.

[ghost]

@farfromrefug You can use _noble.Peripheral.
For ease of use you might want to make a myNoble module with a .d.ts of export * from "noble"; and handle the choosing between modules in there. That way you won't have to repeat that code everywhere.

[farfromrefug]

@andy-ms i can't use _noble.Peripheral in the case where i am requiring 'noble-uwp'. I don't think it would work.
However your idea with the .d.ts might work. Will look at that. Thanks

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.