How to get source of error

I’m writing my first Apollo server/client app and in general I find that when there is an error, the stacktrace appears to just show Apollo internals and not the line in my code where the error originates, making it difficult to pinpoint the problem in my code. Here is an example:

Error: Cannot read property 'casus' of undefined
    at new ApolloError (index.js:29:1)
    at QueryManager.js:592:1
    at both (asyncMap.js:16:1)
    at asyncMap.js:9:1
    at new Promise (<anonymous>)
    at Object.then (asyncMap.js:9:1)
    at (asyncMap.js:17:1)
    at notifySubscription (module.js:132:1)
    at onNotify (module.js:176:1)
    at (module.js:225:1)
    at iteration.js:4:1
    at Array.forEach (<anonymous>)
    at iterateObserversSafely (iteration.js:4:1)
    at (Concast.js:25:1)
    at notifySubscription (module.js:132:1)
    at onNotify (module.js:176:1)
    at (module.js:225:1)
    at createHttpLink.js:103:1

Is there something else I can hook into in order to narrow things down? Maybe the anonymous Promise is from my code, though this seems to be in between Apollo internals so not sure.