How to debug when stack trace includes none of my own code?


#1
TypeError: Cannot convert undefined or null to object
    at keys (native)
    at Function.keys (http://localhost:3000/packages/meteor:/💻app/packages/es5-shim/.npm/package/node_modules/es5-shim/es5-shim.js:954:1)
    at MeteorDataManager.calculateData (http://localhost:3000/packages/meteor:/💻app/meteor-data-mixin.jsx:112:14)
    at [object Object].ReactMeteorData.componentWillMount (http://localhost:3000/packages/meteor:/💻app/meteor-data-mixin.jsx:5:45)
    at [object Object].ReactCompositeComponentMixin.mountComponent (http://localhost:3000/packages/meteor:/💻app/packages/react-runtime-dev/react.browserify.js:6804:1)
    at [object Object].wrapper [as mountComponent] (http://localhost:3000/packages/meteor:/💻app/packages/react-runtime-dev/react.browserify.js:13941:1)
    at Object.ReactReconciler.mountComponent (http://localhost:3000/packages/meteor:/💻app/packages/react-runtime-dev/react.browserify.js:14758:1)
    at [object Object].ReactCompositeComponentMixin.mountComponent (http://localhost:3000/packages/meteor:/💻app/packages/react-runtime-dev/react.browserify.js:6823:1)
    at [object Object].wrapper [as mountComponent] (http://localhost:3000/packages/meteor:/💻app/packages/react-runtime-dev/react.browserify.js:13941:1)
    at Object.ReactReconciler.mountComponent (http://localhost:3000/packages/meteor:/💻app/packages/react-runtime-dev/react.browserify.js:14758:1) undefined

I’m not sure what to do with this. The stack trace doesn’t list any of my own code, so I can’t even begin to figure out where I did something wrong. How does one go about debugging something like this?


#2

It’s not entirely clear how the OP got to this error, but I just recently encountered it with a similar stack trace. In the event anyone else trips over this while investigating, in my case, the problem was that I was not actually returning anything from the function passed into a createContainer call.


#3

I think the question is not about specific error but more widely, how to debug application with such stacktraces. Is it something that everyone faces often? (I do) Is it something that meteor should improve (if so then its very important!). Maybe I am doing something wrong for getting such stacktraces? How are other developers approach this problem or no one gets it? I asked similar question: How to get clear stack trace messages but no answers. Clear and informative stack traces are very important feature and in larger application can be a deal breaker when choosing a framework/language for a project.


#4

It’s obligatory return an object!