Generate a colour within a range based on a value

colour_generator.js

  function Interpolate(start, end, steps, count) {
    var s = start,
        e = end,
        final = s + (((e - s) / steps) * count);
    return Math.floor(final);
  }

  function Color(_r, _g, _b) {
    var r, g, b;
    var setColors = function(_r, _g, _b) {
      r = _r;
      g = _g;
      b = _b;
    };

    setColors(_r, _g, _b);
    this.getColors = function() {
      var colors = {
          r: r,
          g: g,
          b: b
      };
      return colors;
    };
  }

  function strokeColour(val){
    var arrayOfVals = [10,20,30,40,50],
        max = parseFloat(arrayOfVals[(arrayOfVals.length - 1)]),
        min = parseFloat(arrayOfVals[0]),
        average = ((max + min)/2).toFixed(),
        val = ((parseFloat(val)/average)*100).toFixed(),
        light_blue = new Color(127, 127, 255), // #0000fb #7f7fff
        blue = new Color(198, 127, 184), // #800080 #c67fb8
        red = new Color(255, 127, 127), // #ff0000 #ff7f7f
        start = light_blue,
        end = blue;

    if (val > 50) {
      start = blue,
        end = red,
        val = val % 51;
    }

    var startColors = start.getColors(),
        endColors = end.getColors();
    var r = Interpolate(startColors.r, endColors.r, 50, val);
    var g = Interpolate(startColors.g, endColors.g, 50, val);
    var b = Interpolate(startColors.b, endColors.b, 50, val);

    return "rgb(" + r + "," + g + "," + b + ")";
  }
  
  strokeColour(25)