How to locally add types to untyped npm modules in typescript?

Question

I know this has been asked an answered elsewhere since at least 2017, but I can't make this work. I have noImplicitAny: true in my tsconfig.json in my project. I'm trying to use clamscan which is neither natively typed nor available in @types. My question is not specific to this package.

So when I import NodeClam from 'clamscan' in code.ts I get the following error:

Could not find a declaration file for module 'clamscan'. '.../node_modules/clamscan/index.js' implicitly has an 'any' type.
Try `npm install @types/clamscan` if it exists or add a new declaration (.d.ts) file containing `declare module 'clamscan';`ts(7016)

So I created a clamscan.d.ts file with:

declare module 'clamscan' {
  // the declarations I use
}

I also tried simply declare module 'clamscan';. In both cases I get:

Invalid module name in augmentation. Module 'clamscan' resolves to an untyped module at '.../node_modules/clamscan/index.js', which cannot be augmented.ts(2665)

On the other hand, declare module '*'; is accepted by the compiler but isn't quite what I want (and doesn't solve the original error anyways). So, how can I type an untyped foreign npm module ?

I understand that I can contribute to DefinitlyTyped or the clamscan package, but the question is about annotating/augmenting the package locally just for my project.

I suspect typescript can't find your declarations file. Try putting in at the path src/@types/clamscan/index.d.ts or src/@types/clamscan.d.ts. Or editing the typeRoots property in your .tsconfig to include the path where you have stored it. I get the "invalid module..." error if I've declared the type after the module has already been imported. — Linda Paiste
– Linda Paiste, Commented Sep 30, 2020 at 21:07
Thanks for the tip. Can't make it work anywhere in src/ but I put it in node_modules/@types/clamscan/index.d.ts for now. Gonna play with typeRoots to see if I can do better. — Antoine
– Antoine, Commented Oct 2, 2020 at 10:34
@DouglasGaskell not really, I worked in node_modules/@types, which is not ideal obivously, so I ended up having my type definitions merged in the upstream package, so that it can be useful to others - so I guess problem solved, but I don't have a technical solution for my original issue — Antoine
– Antoine, Commented Feb 12, 2021 at 9:08

Edward Casanova · Accepted Answer · 2021-03-17 16:47:16Z

2

Try this:

declare module 'clamscan' {
   import * as Clamscan from 'clamscan';
  export default Clamscan
}

or create a single file with only this inside "clamscan.d.ts"

declare module 'clamscan' {
       import * as Clamscan from 'clamscan'; // or import Clamscan from "clamscan" or import {Clamscan} from "clamscan" . It depends of how the import is handled
    }

If this doesn't work take a look at this solution

edited Mar 17, 2021 at 16:47

answered Mar 17, 2021 at 16:38

Edward Casanova

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Edwin Joassart · Accepted Answer · 2022-09-02 14:24:04Z

0

Had to do this for it to work with digest-stream :

declare module "digest-stream" {
  export default function digestStream(algorithm: string, inputEncoding: string, digestEncoding?: any, options?: any, listenerFn?: any): any
}

answered Sep 2, 2022 at 14:24

Edwin Joassart

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