Observed on https://en.wikipedia.org/wiki/Internet#Social_impact
When dragging on the visualization in Firefox, I can trigger the error "TypeError: datum.firstYear is undefined"
In Chrome this appears as "Cannot read property 'value' of undefined".
The same graph seems to be associated with "RangeError: Invalid array length"
at Collector.proto.values URL1:308:99 at Facetor.proto.changes URL1:306:618 at Aggregate.prototype.transform URL1:632:317 at Aggregate.prototype.evaluate URL1:672:151 at Scale.dataRef URL1:598:955 at Scale.domainMinMax URL1:599:762 at Scale.quantitative URL1:595:831 at Scale.scale URL1:592:971 at fn URL1:592:300 URL1: https://en.wikipedia.org/w/load.php?lang=en&modules=ext.graph.data%2Cvega2%7Cext.scribunto.logs%7Cjquery%7Cjquery.makeCollapsible%2Cthrottle-debounce%7Cmediawiki.page.gallery%7Cmediawiki.toc&skin=vector&version=pbe7f
Note this error is not being logged as much as it should be due to a bug in the instrumentation code (see T277902), and can be trigged multiple times, so is very dangerous left unfixed.
The same graph also shows the error:
SyntaxError: Failed to execute 'addColorStop' on 'CanvasGradient': The value provided ('#NaNNaNNaN') could not be parsed as a color.
at gradient URL1:485:828
at color URL1:485:586
at Object.fill URL1:485:114
at CanvasRenderer.draw URL1:479:585
at CanvasRenderer.prototype.draw URL1:472:511
at CanvasRenderer.draw URL1:475:406
at CanvasRenderer.prototype.draw URL1:472:511
at CanvasRenderer.draw URL1:475:566
at CanvasRenderer.prototype.draw URL1:472:511
at CanvasRenderer.draw URL1:475:406
URL1: https://en.wikipedia.org/w/load.php?lang=en&modules=ext.graph.vega2%7Cjquery&skin=vector&version=bh9hy