Function composition for type conversion

gistfile1.js

function makeConverter(pairs) {

  function converter(value) {

    for(var i = 0; i < pairs.length; i++) {
      var predicate = pair[0];
      var func = pair[1];
      if(predicate(value)) {
        return converter(func(value));
      }
    }

    // if no predicate is satisfied, then just return original value
    return value;
  }

  return converter;
}

// `convertColor` will be smart enough to know which conversion to perform based on input type
convertColor = makeConverter([
  [isColorName, colorNameToHex],
  [is256Color, color256ToHex],   // this pair plus next pair can lead to converting 256 to Name if untilFixedPoint is used
  [isHexColor, colorHexToName]
]);

convertColor('green') == colorNameToHex('green');