CORS origin custom function throw and crash the app

[ludohenin]

Steps to reproduce

Setting the origin to a custom function make the app crash if an error is passed to the callback function.

corsConfig.origin = function customOrigin(origin, callback) {
  if (whitelist.indexOf(origin) !== -1) {
    callback(null, true);
  } else {
    callback(new HttpErrors.Forbidden('Not allowed by CORS'));
  }
};

Current Behavior

/home/ludohen/github/ta-api-core-2/node_modules/@loopback/rest/dist/rest.server.js:616
            throw err;

Expected Behavior

send a response with the correct error code.