Transformation for custom value in SparklinesReferenceLine

[Dem0n3D]

  <Sparklines data={this.props.data}>

        <SparklinesLine />

        <SparklinesReferenceLine type="custom" value={point.y} />

  </Sparklines>

in this PR, point.y will be transformed with dataToPoints (max in min will be calculated automatically in Sparklines).

[borisyankov]

Maybe we can move this to some other parts of the app?
And keep this simple?

[Dem0n3D]

As you wish. I just want to make SparklinesReferenceLine works in expected way.

[isaacsanders]

Why does the min and max need to be calculated here? The Sparklines component doesn't do any additional calculations and the dataToPoints function backfills the missing information. The second commit seems extraneous.

[Dem0n3D]

Look at this:

const data = type == 'custom' ? [value] : dataProcessing[type](ypoints);

const y = dataToPoints({ data, limit, width, height, margin, max, min })[0].y;

here dataToPoints gets already transformed data (just one point in many cases), so it has no idea about original data array, and it can't calculate correct min and max.
SparklinesReferenceLine, in other side, don't gets original data too. So, we have that min and max of original data array should be calculated in the top level component.

[MattVoda]

Hey, any progress on this?