ValueMapper - normalise and transform - great for converting a number from one range to a different range

ValueMapper

var ValueMapper = {
    normalise: function(value, low, high) {
        var range = high - low;
        return (value - low) / range;
    },
        
    transform: function(value, inputLow, inputHigh, outputLow, outputHigh) {
        var normal = this.normalise(value, inputLow, inputHigh);
        return normal * (outputHigh - outputLow) + outputLow;
    }
}