Application dies when switching storytelling branches

[keckelt]

Hi,

I had the following error when switching a branch in the storytelling pane:

Storytelling.tsx:121 Uncaught TypeError: Cannot read property 'y' of undefined
    at Storytelling.tsx:121
    at Array.map (<anonymous>)
    at _loop (Storytelling.tsx:94)
    at Storytelling.tsx:89
    at ProvenanceGraph.render (Storytelling.tsx:87)
    at finishClassComponent (react-dom.development.js:17160)
    at updateClassComponent (react-dom.development.js:17110)
    at beginWork (react-dom.development.js:18620)
    at HTMLUnknownElement.callCallback (react-dom.development.js:188)
    at Object.invokeGuardedCallbackDev (react-dom.development.js:237)
(anonym) @ Storytelling.tsx:121
_loop @ Storytelling.tsx:94
(anonym) @ Storytelling.tsx:89
render @ Storytelling.tsx:87
finishClassComponent @ react-dom.development.js:17160
updateClassComponent @ react-dom.development.js:17110
beginWork @ react-dom.development.js:18620
callCallback @ react-dom.development.js:188
invokeGuardedCallbackDev @ react-dom.development.js:237
invokeGuardedCallback @ react-dom.development.js:292
beginWork$1 @ react-dom.development.js:23203
performUnitOfWork @ react-dom.development.js:22157
workLoopSync @ react-dom.development.js:22130
performSyncWorkOnRoot @ react-dom.development.js:21756
(anonym) @ react-dom.development.js:11089
unstable_runWithPriority @ scheduler.development.js:653
runWithPriority$1 @ react-dom.development.js:11039
flushSyncCallbackQueueImpl @ react-dom.development.js:11084
flushSyncCallbackQueue @ react-dom.development.js:11072
discreteUpdates$1 @ react-dom.development.js:21893
discreteUpdates @ react-dom.development.js:806
dispatchDiscreteEvent @ react-dom.development.js:4168
react-dom.development.js:19527 The above error occurred in the <ProvenanceGraph> component:
    in ProvenanceGraph
    in div
    in div
    in div
    in div (created by ForwardRef(Paper))
    in ForwardRef(Paper) (created by WithStyles(ForwardRef(Paper)))
    in WithStyles(ForwardRef(Paper)) (created by ForwardRef(Card))
    in ForwardRef(Card) (created by WithStyles(ForwardRef(Card)))
    in WithStyles(ForwardRef(Card))
    in Unknown (created by ConnectFunction)
    in ConnectFunction (created by _class)
    in div (created by _class)
    in div (created by _class)
    in _class (created by ConnectFunction)
    in ConnectFunction
    in ThemeProvider
    in Provider

Consider adding an error boundary to your tree to customize error handling behavior.
Visit https://fb.me/react-error-boundaries to learn more about error boundaries.
logCapturedError @ react-dom.development.js:19527
logError @ react-dom.development.js:19564
update.callback @ react-dom.development.js:20708
callCallback @ react-dom.development.js:12490
commitUpdateQueue @ react-dom.development.js:12511
commitLifeCycles @ react-dom.development.js:19883
commitLayoutEffects @ react-dom.development.js:22803
callCallback @ react-dom.development.js:188
invokeGuardedCallbackDev @ react-dom.development.js:237
invokeGuardedCallback @ react-dom.development.js:292
commitRootImpl @ react-dom.development.js:22541
unstable_runWithPriority @ scheduler.development.js:653
runWithPriority$1 @ react-dom.development.js:11039
commitRoot @ react-dom.development.js:22381
finishSyncRender @ react-dom.development.js:21807
performSyncWorkOnRoot @ react-dom.development.js:21793
(anonym) @ react-dom.development.js:11089
unstable_runWithPriority @ scheduler.development.js:653
runWithPriority$1 @ react-dom.development.js:11039
flushSyncCallbackQueueImpl @ react-dom.development.js:11084
flushSyncCallbackQueue @ react-dom.development.js:11072
discreteUpdates$1 @ react-dom.development.js:21893
discreteUpdates @ react-dom.development.js:806
dispatchDiscreteEvent @ react-dom.development.js:4168
Storytelling.tsx:121 Uncaught TypeError: Cannot read property 'y' of undefined
    at Storytelling.tsx:121
    at Array.map (<anonymous>)
    at _loop (Storytelling.tsx:94)
    at Storytelling.tsx:89
    at ProvenanceGraph.render (Storytelling.tsx:87)
    at finishClassComponent (react-dom.development.js:17160)
    at updateClassComponent (react-dom.development.js:17110)
    at beginWork (react-dom.development.js:18620)
    at HTMLUnknownElement.callCallback (react-dom.development.js:188)
    at Object.invokeGuardedCallbackDev (react-dom.development.js:237)

The whole page was blank/white then and i had to refresh.