Declaration file for class-module (TypeScript)

Question

I use a node module that's not found by typings and doesn't exist in definelytyped.

the basic use of the module is:

import * as SomeClass from 'some-module';

var someObject = new SomeClass("some string");
someObject.someMethod();

As you can see, this module exports a class as its default. I haven't figured out how to write the declaration file for it.

This is the best I managed to do:

declare module 'some-module' {
    export default class SomeClass {
        constructor (someArg: string);
        someMethod(): void;
    }
}

BTW it does work JavaScriptly. It's only the TypeScript bothers me.

Any ideas how to solve that?

Are you transpiling your code down to es5? If you do, then I would recommend you to use import SomeClass = require('some-module') instead....it's a long story short — unional
– unional, Commented Mar 26, 2017 at 3:25

unional · Accepted Answer · 2017-04-04 23:23:03Z

3

For the declaration, you need to do this:

declare module 'some-module' {
    class SomeClass {
        constructor (someArg: string);
        someMethod(): void;
    }
    namespace SomeClass {}
    export = SomeClass;
}

UPDATE: Thank you to Blake Embrey for pointing out, the hack namespace SomeClass {} is needed to get this working. see https://github.com/Microsoft/TypeScript/issues/5073 for more detail.

edited Apr 4, 2017 at 23:23

answered Mar 26, 2017 at 3:27

unional

15.8k6 gold badges36 silver badges57 bronze badges

Sign up to request clarification or add additional context in comments.

8 Comments

Alon Over a year ago

It produces an error: 'TS2497: Module '"some-module"' resolves to a non-module entity and cannot be imported using this construct.' on the import statement. I transpile to ES6 BTW.

unional Over a year ago

You need to put it in a separate file. Not in a file with top-level import/export. Save it as custom-typings/some-module.d.ts and include it in your tsconfig.json.

unional Over a year ago

Is it an application or a package?

unional Over a year ago

shoot, seems like something changed in 2.2 and this does not work anymore. Need to figure out what's the alternative myself.

Alon Over a year ago

It's in a separate file. I've created some declaration files already. I know how to do that. It's just a special case because it has a default export which is a class.

|

OrcusZ · Accepted Answer · 2017-03-23 15:20:52Z

0

If you just want to avoid TypeScript error and do not worry about ItelliSense just declare your class library like that in the begining of you file for example:

declare var SomeClass: any;

answered Mar 23, 2017 at 15:20

OrcusZ

3,6822 gold badges33 silver badges50 bronze badges

Collectives™ on Stack Overflow

Declaration file for class-module (TypeScript)

2 Answers 2

8 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

8 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related