Keystone.js throws unhandled exception when auth fails

If I use bad credentials (bad password or domain for example) I get an unhandled exception from keystone.js when calling keystone.getToken():

Uncaught TypeError: Cannot set property 'token' of undefined
at Request._callback (node_modules/openstack-wrapper/lib/keystone.js:138:22)
at Request.self.callback (node_modules/request/request.js:185:22)
at Request. (node_modules/request/request.js:1161:10)
at IncomingMessage. (node_modules/request/request.js:1083:12)
at endReadableNT (_stream_readable.js:1064:12)
at _combinedTickCallback (internal/process/next_tick.js:138:11)
at process._tickDomainCallback (internal/process/next_tick.js:218:9)

The problem seems to be that the code is expecting body.token to always exist, but in this case I can see the body is: {"error":{"message":"The request you have made requires authentication.","code":401,"title":"Unauthorized"}}

I'm using node.js v 8.11 (but same thing found in v 8.14 as well).