Wavelength-To-RGB

index.js

var color = function(wavelength) {
  var bounds = [380,  440,  490,  510,  580,  645, 780];
	var pairs  = ["BR", "BG", "GB", "GR", "RG", "R"]
	var colorGen = function(combo, borders, wl) {
		var RGB = {R:0,G:0,B:0};
		RGB[combo[0]] = 255;
		RGB[combo[1]] = 255 * (borders[1] - wl)/(borders[1] - borders[0]);
		return RGB;
	};
	var residuals = bounds.map(function(bound){return bound-wavelength}).map(Math.abs);
	var floorIndex = residuals.indexOf(Math.min.apply(Math, residuals));
	var borders = [ bounds[floorIndex], bounds[floorIndex+1] ];	// [floor, ceiling]
	return colorGen(pairs[floorIndex].split(''), borders, wavelength);
};