TS2326: Types of property 'sub' are incompatible. Type 'string' is not assignable to type '() => string'.

[alexbjorlig]

I don't know if this is a typings bug, or a library issue.

With the following versions:
"@types/jsonwebtoken": "^8.3.0"
"jsonwebtoken": "^8.3.0"

The following snippet:

const jsonWebToken = jwt.sign({
            user_id, // The userID
            sub: 'some-sub', // The id from above
            ulimit: 2 // The usage limit
        }, 'shh');

throws the error:

TS2326: Types of property 'sub' are incompatible.
  Type 'string' is not assignable to type '() => string'.

But if I look at the typings:

export function sign(
    payload: string | Buffer | object,
    secretOrPrivateKey: Secret,
    options?: SignOptions,
): string;

It looks correct?

Workaround:

const jsonWebToken = jwt.sign({
            user_id, // The userID
            sub: 'some-sub', // The id from above
            ulimit: 2 // The usage limit
        } as any, 'shh');

If the sub property indeed needs to be () => string I would happily like to assist with the PR to the typings, but I am not sure what the problem is 🤷🏽‍♂️

[amrew]

I also got the problem.
You can cast it sub: 'some-sub' as any. Temporary solution

const jsonWebToken = jwt.sign({
            user_id, // The userID
            sub: 'some-sub' as any, // The id from above
            ulimit: 2 // The usage limit
        } as any, 'shh');

[LoicPoullain]

The weird thing is that the types look correct: https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/jsonwebtoken/index.d.ts#L121 🤔

[LoicPoullain]

It looks like it is a compiler issue. It works with TypeScript 3.4.5 but fails with TypeScript 3.5.1 & 3.5.2.

[alexbjorlig]

@LoicPoullain good catch - but why does it fail with Typescript > 3.5.1 🤷🏽‍♂️ ?

[LoicPoullain]

No idea 😕 I'm going to open an issue on the TS repo today when I get a chance.

[LoicPoullain]

Looks like the bug is fixed in the pending next version of TypeScript. Installing typescript@next (version 3.6.0-dev.20190623) makes the compilation work. We just need to wait for the next release and build with 3.4 for now.

[panva]

I'm going to go ahead and close this as a) it's resolved, b) there's no TODO in this repo or the types one, which we're not the maintainers of btw.