How to combine two hapi.js authentication strategies which both use a bearer token from the authorization request header (hapi auth scheme for ambiguous token). ES6 with async/await.

hapiAmbiguousBearerTokenAuthScheme.js

const Boom = require('boom');

const headerPattern = /^Bearer (.+)/;

const testAuth = (request, strategy) => new Promise((resolve, reject) => {
  request.server.auth.test(strategy, request, (error, credentials) => {
    if (error === null) {
      resolve(credentials);
    } else {
      reject(error);
    }
  });
});

/*
 * Derive auth strategy to be used from the bearer token.
 */
const strategyForToken = (token) => {
  let strategy = false;
  if (conditionToDetectFirstStrategy) {
    strategy = 'firstStrategyHere';
  } else if (conditionToDetectSecondStrategy) {
    strategy = 'secondStrategyHere';
  }

  return strategy;
};

/*
 * Extract bearer token from request and identify which auth strategy it is meant for.
 */
const authenticate = async (request, reply) => {
  // Reject missing or invalid header.
  const header = request.headers.authorization;
  if (!header || !headerPattern.test(header)) {
    return reply(Boom.badRequest('Missing or invalid authorization header'), {}, {});
  }

  const token = header.match(headerPattern)[1];
  const strategy = strategyForToken(token);

  if (!strategy) {
    return reply(Boom.badRequest('Unable to determine auth strategy'), {}, {});
  }

  try {
    const credentials = await testAuth(request, strategy);

    // Remember which strategy was successfully tested.
    const artifacts = { actualStrategy: strategy };

    return reply.continue({ credentials, artifacts });
  } catch (error) {
    return reply(error, {}, {});
  }
};

module.exports = {
  scheme: () => ({ authenticate })
};