Property 'nonce_supported' does not exist on type 'string | JwtPayload'

[benbai123]

Description

@types/jsonwebtoken 8.5.8 break the nestjs application,

sample code

import * as jwt from 'jsonwebtoken';

//  identityToken, nonce are props from apple signin

const decoded = jwt.decode(identityToken, { complete: true });

// ...

if (decoded.payload.nonce_supported && nonce !== NONCE) {
  // ...
}

if (!decoded.payload.iss || decoded.payload.iss !== APPLE_BASE_URL) {
  // ...
}

if (decoded.payload.aud !== 'my.aud.string') {
  // ...
}

if (Number(decoded.payload.exp) * 1000 < my_expr_limit) {
  // ...
}

error message:

Property 'nonce_supported' does not exist on type 'string | JwtPayload'.
  Property 'nonce_supported' does not exist on type 'string'.

Property 'iss' does not exist on type 'string | JwtPayload'.
  Property 'iss' does not exist on type 'string'.

Property 'aud' does not exist on type 'string | JwtPayload'.
  Property 'aud' does not exist on type 'string'.

Property 'exp' does not exist on type 'string | JwtPayload'.
  Property 'exp' does not exist on type 'string'.

Reproduction

1. create a nestjs app
2. add "jsonwebtoken": "^8.5.1", to your package.json
3. implement apple sign in as the sample above
4. npm install
5. npm run start then you can see the errors

Environment

Please provide the following:

• Version of this library used: 8.5.1
• Version of the platform or framework used, if applicable: node 16.13.1, npm 8.1.2
• Other relevant versions (language, server software, OS, browser): OS Mac M1
• Other modules/plugins/libraries that might be involved: "@types/jsonwebtoken": "8.5.8",

[benbai123]

Workaround

specify dependency "@types/jsonwebtoken": "8.5.4", in your package.json

[cavewebs]

We can fix the error by either using const jwt = require('jsonwebtoken');

Or since Typescript cannot infer the correct type and therefore expand other items available in jwt.payload are not known, the simplest way out is to cast the result to anyin this manner const token: any = jwt.decode()

[anantakrroy]

We can fix the error by either using const jwt = require('jsonwebtoken');

Or since Typescript cannot infer the correct type and therefore expand other items available in jwt.payload are not known, the simplest way out is to cast the result to anyin this manner const token: any = jwt.decode()

Using any type defeats the purpose of using Typescript and should be avoided.

[CompeyDev]

I worked around this by using a typeof expression checking if the type is not a string, but rather a JwtPayload. But looks like it returns a string, why? Is there a way to force JWT to only return a payload?

[Naumov1889]

this problem still exists. In docs it says

(Synchronous) If a callback is not supplied, function acts synchronously. Returns the payload decoded if the signature is valid and optional expiration, audience, or issuer are valid. If not, it will throw the error.

But when I try to access payloads properties, ts error accrues arguing about property doesn't exists on type string.

[rswdch]

Isn't this more of a problem with the @types/jsonwebtoken package than jsonwebtoken itself? It seems like the types package is saying that the type returned by decode can be string | JwtPayload but I don't see any indication that a string will be returned by decode. It actually does a type check for string and tries to convert strings to objects.

You could probably safely assert as JwtPayload, otherwise type checking for a string would be the other TypeScript-friendly solution.

We should probably file this as an issue on the DefinitelyTyped repo.