Cannot read property '0' of null in clipCells() about d3-voronoi HOT 13 CLOSED

I discovered there was a problem in an intermediate library which calls into d3. The problem was that the other library defined a callBack() function in d3.voronoi().y(callBack). The callBack() function would sometime return data that was incorrect.

Sorry for the confusion.

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I’d like to look into this, but without a test case that reproduces the error, I’m not sure where to start.

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Thanks for letting me know.

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also experiencing just this issue. it's also hard for me to reproduce the error with the same data in a single page example.

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@brwebb do you remember how your data was sometimes incorrect?

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here's a working example with the exact data that fails in my larger project http://bl.ocks.org/micahstubbs/2e7c882e69aa10d9dc317b59baf64692

now to go figure out if something is transforming the data in the middle of the larger project before it gets to d3.voronoi() 💭

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Unfortunately I don't remember the details. However, I think it had something to do with processing data points where the x or y value did not exist, maybe 0 or null.

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@brwebb, thanks all the same! it looks like sparse data with lots of 0 values is the issue for me

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@mbostock managed to make a minimal example that reproduces the issue
Voronoi clipCells() end[1] null Example II

this second example, though less minimal, logs out internal values from d3 to the console to perhaps shed some light on the error message
Voronoi clipCells() end[1] null Example III

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it looks like this could be the cause #12

thanks to @Fil for the answer over on slack

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for voronoi you're not allowed to have two points at the same coords

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i'm also seeing this error in the same clipCells function. have spent many hours on this and made no progress

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@AlexanderBollbach is there a minimal example of the place you experience the error that you can share?

(nice to see others encounter this same specific issue as I did 😄 )

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