Heatmap breaks when rendering colors

[mischabraam]

Every now and then the function getGradientColor throws an exception.
For example this happens with the following data.

{
	"labels": ["00:00", "00:00"],
	"datasets": [{
		"label": "2018",
		"data": [-4.135, -4.437]
	}]
}

See fiddle

[mischabraam]

Probably related to #2 and fixed by #6

[mischabraam]

I can confirm the relation. When I multiply all values by 10 it works.