add support to hide tooltips, key => seriesKey to avoid React prop clash.

[williaster]

this PR makes the following improvements 🚀

• [shared][tooltip] don't render a tooltip if the output of renderTooltip is falsy
• breaking [xy-chart] use seriesKey instead of key in onMouseMove event signature (relevant to StackedBarSeries and GroupedBarSeries only)

cc @alecklandgraf

[alecklandgraf]

what do you think about duplicating key with seriesKey (or stackedKey)? it would make this backward compatible.

[coveralls]

Coverage increased (+0.03%) to 83.212% when pulling 7446444 on chris--falsy-tooltip into 49733e9 on master.

[alecklandgraf]

I don't think you need the ternary. This should work just fine:

const tooltipContent = renderTooltip && tooltipOpen && TooltipComponent && renderTooltip(tooltipData);

...
{toolTipContent && <TooltipComponent ... />

[alecklandgraf]

Looks good! One comment

[williaster]

thanks for the comments.

I'd rather not always pass key around since it's reserved in React, we haven't been avoiding breaking changes in vx or data-ui until we hit a major version just so we can land on better apis. I think that seriesKey is slightly better than stackKey because it can be used by stacked + grouped bar series.

[coveralls]

Coverage increased (+0.02%) to 83.206% when pulling f88831a on chris--falsy-tooltip into 49733e9 on master.