"TypeError: cb is not a function" when providing a native async function to options.secret

I narrowed it down to the “isFunction” check at: https://github.com/auth0/express-jwt/blob/master/lib/index.js#L10. Since the async function is not correctly recognized as a function (Object.prototype.toString.call(object) returns [object AsyncFunction]), the provided “secret” callback is wrapped by the default callback provided by “wrapStaticSecretInCallback”.

The following options.secret function replicates the error:

async function secretProvider(req, header, payload, cb) {
   cb();
}

To fix the error, I would like to submit a PR to replace the isFunction check with the https://www.npmjs.com/package/lodash.isfunction package which detects async functions.

[jfromaniello]

Sorry for the long delay, this is fixed in v7

[rebolyte]

@KalleV @jfromaniello I just got bitten by this as well. Could we get one of the open PRs merged?