how to get public key from getSigningKey function of jwks-rsa - node.js

Question

i have tried two library of nodejs "jwks-rsa" and "jwks-client" to get public key to authenticate Apple login. But its giving error in getPublicKey is not a function.
Then i console the key which is return by getSigningKey is giving me -1.
i don't know why this is behaving like that.
const header = token.split(".");
const jwtHead = Buffer.from(header[0], "base64").toString();
const kid = JSON.parse(jwtHead).kid;
const jwksClient = require('jwks-client');
const client = jwksClient({
strictSsl: true, // Default value
jwksUri: process.env.APPLE_URL
});
client.getSigningKey(kid, (err, key) => {
console.log(key)
const signingKey = key.publicKey;
console.log(signingKey);
});

Answer 1

For me it works as expected I've try it with your configuration:
const kid = '86D88Kf'; // specify kid explicitly
const client = jwksClient({
strictSsl: true,
jwksUri: 'https://appleid.apple.com/auth/keys'
});
client.getSigningKey(kid, (err, key) => {
console.log(key)
const signingKey = key.publicKey;
console.log(signingKey);
});
And I get a legit public key in the response:
Probably you have some misconfiguration.

Answer 2

The problem is with the find() method used inside getSigningKey(kid).find() method has compatibility issues find() compatibility issue. We can use filter() method instead.
Instead of using client.getSigningKey(kid) try using keys = client.getSigningKeys() then filter the response const key = keys.filter(k => k.kid === kid);