Trying to convert a PEM public key to JWK

[dagnelies]

What happened?

Hi,

I'm trying to convert the PEM public key as follows:

  const publicPem = "-----BEGIN PUBLIC KEY-----...."
  const publicKey = await jose.importSPKI(publicPem, 'RS256', {extractable:true})
  console.log(publicKey)
// OK, prints "CryptoKey {...}"

  const publicJwk = await jose.exportJWK(publicKey) // <- Error
  console.log(publicJwk)

But it generates the following error:

TypeError: Right-hand side of 'instanceof' is not an object
    at isCryptoKey (...\node_modules\jose\dist\browser\runtime\webcrypto.js:2:37)
    at keyToJWK (...\node_modules\jose\dist\browser\runtime\key_to_jwk.js:12:10)
    at exportJWK (...\node_modules\jose\dist\browser\key\export.js:11:12)

Strangely enough the code works when deployed on Cloudflare.

Here is the related code: https://github.com/panva/jose/blob/main/src/runtime/browser/key_to_jwk.ts

I think it has to do with the node vs browser runtime, it is a bit weird though.

Version

4.11.2

Runtime

Cloudflare Workers

Runtime Details

Node v19.4.0 / Wrangler

Code to reproduce

const publicPem = "-----BEGIN PUBLIC KEY-----...."
  const publicKey = await jose.importSPKI(publicPem, 'RS256', {extractable:true})
  console.log(publicKey)
// OK, prints "CryptoKey {...}"

  const publicJwk = await jose.exportJWK(publicKey) // <- Error
  console.log(publicJwk)

Required

• I have searched the issues tracker and discussions for similar topics and couldn't find anything related.
• I agree to follow this project's Code of Conduct

[panva]

Node v19.4.0 / Wrangler

Sorry @dagnelies, I have no clue how to replicate this.

Strangely enough the code works when deployed on Cloudflare.

Not strange at all.

Obviously the problem is not with the library but whatever runtime you're executing your code in - it lacks the CryptoKey in its globals.

• CF Workers (workerd) is part of the CI pipeline and the WebCryptoAPI runtime build works there.
• Node v19.x is also part of the CI pipeline and the WebCryptoAPI build works there too because WebCryptoAPI is finally made global in 19.x onward.

[panva]

If this is the same runtime issue miniflare had, downgrading to v18.x node will help. Be sure to open an issue with your respective runtime.

Ref: cloudflare/miniflare#457

[dagnelies]

Thanks for checking. It is indeed an issue with miniflare.