When using domain in the colorAxis for a HeatMap, the color legend disappears.

example:

Code:
colorAxisScale = {
          type: 'linear', 
          domain: [ 0, 0.001, 100],
          range: ['white', '#c62828','#1565c0']
};
Why set domain to 0 and then 000.1 ? = to get 0 values to be White and be sure that values like 0.5 or 3 don't.
Have tried using the processor() method but it doesnt seem to work.