Mapping [0,1] to a hex color.

ZeroOneToString.js

var c = function(n) {
  var string = '';
  n = Math.floor(n * Math.pow(256, 3));
  
  for (var i = 5; i >= 0; i--) { 
    string += (Math.floor(n / Math.pow(16, i)) % 16).toString(16);
  }
  
  return '#' + string;
}