Hi @firojasha ,

Encountered the same issue today and after 30 minutes of searching managed to track it down to this commit / line:
74f6fe3#diff-b52768974e6bc0faccb7d4b75b162c99R58

Sadly there was no mention of this breaking change anywhere nor was there documentation update.

Working solution for now is:

const getKey = (header, callback) => {
      client.getSigningKey(header.kid, (err, key: jwksClient.SigningKey) => {
        const signingKey =
          (key as jwksClient.CertSigningKey).publicKey ||
          (key as jwksClient.RsaSigningKey).rsaPublicKey
        callback(null, signingKey)
      })
}

+1 having the same error. Downgrading version for now

Is there any update on this, please?

upgraded today from 1.5.0 and facing the same issue.

experiencing the same issue

For those encountering this issue, we sincerely apologize for the unexpected breaking change. We are evaluating the best path forward to address this; in the meantime please remain on version 1.5 if you don't need to support private certificates and/or additional agent configurations that was added in v6, or consider the suggested workarounds above.

Hi all. Considering the time passed since the unintended breaking change, we've released version 1.6.2 which includes a quick way to obtain the Public Key value, and resolve any TS definitions conflicts that were introduced with 1.6.0.

Now, instead of type-checking the value and accessing either key.publicKey or key.rsaPublicKey properties, you can directly invoke the key.getPublicKey() function:

const getKey = (header, callback) => {
      client.getSigningKey(header.kid, (err, key: jwksClient.SigningKey) => {
        const signingKey = key.getPublicKey()
        callback(null, signingKey)
      })
}

We apologize for any inconvenience that this has caused.

@lbalmaceda please update readme example at https://github.com/auth0/node-jsonwebtoken#jwtverifytoken-secretorpublickey-options-callback with above too if its the suggested way now