code: function brightColor(layerId, alpha) {
    var luminosity = 'bright';
    var hue = null;
  
    if (/water|ocean|lake|sea|river/.test(layerId)) {
      hue = 'blue';
    }
  
    if (/state|country|place/.test(layerId)) {
      hue = 'pink';
    }
  
    if (/road|highway|transport/.test(layerId)) {
      hue = 'orange';
    }
  
    if (/contour|building/.test(layerId)) {
      hue = 'monochrome';
    }
  
    if (/building/.test(layerId)) {
      luminosity = 'dark';
    }
  
    if (/contour|landuse/.test(layerId)) {
      hue = 'yellow';
    }
  
    if (/wood|forest|park|landcover/.test(layerId)) {
      hue = 'green';
    }
  
    var rgb = randomColor({
      luminosity: luminosity,
      hue: hue,
      seed: layerId,
      format: 'rgbArray'
    });
  
    var rgba = rgb.concat([alpha || 1]);
    return 'rgba(' + rgba.join(', ') + ')';
  }
docs: Assign a color to a unique layer ID and also considering
  common layer names such as water or wood.
  @param {string} layerId
  @return {string} Unique random for the layer ID