gistfile1.txt

var magicNumberFinder = (function () {
	var knownMagicNumbers = [], cacheUsedCount = 0, cacheSize = 0;
	
	function stringImpl(num) {
		var sum = 0,
			prod = 1,
			currentNum = "",
			stringNum = ""+num;
		
		for (i=0;i<stringNum.length;i++) {
			currentNum = parseInt(stringNum.charAt(i));
			sum += currentNum;
			prod = prod*currentNum;
		}

		return sum === prod;
	}
	
	function modImpl (num) {
		var sum = 0,
			prod = 1,
			mod;
		
		while (num>=10) {
			mod = num%10;
			num = Math.floor(num/10);
			sum += mod;
			prod = prod*mod;
		}
		//a little ugly doing this once more out of the loop.
		sum += num;
		prod = prod*num;
		
		return sum === prod;
		
	}
	
	return {
		isMagic: function (num, method) {
			// console.log(num);
			//if it is known, don't recalculate
			if (knownMagicNumbers[num] === undefined) {
				if (!method) {
					knownMagicNumbers[num] = modImpl(num);
				} else {
					knownMagicNumbers[num] = stringImpl(num);
				}
				cacheSize++;
			} else {
				cacheUsedCount++;
			}
			return knownMagicNumbers[num];
		},
		cacheStats: function (maxLoops) {
			console.log("cache size: " + cacheSize + ", used " + cacheUsedCount + " times");
			console.log("cache used: " + (cacheUsedCount/maxLoops)*100 + "%");
		},
		wipeCache: function () {
			knownMagicNumbers = [], cacheUsedCount = 0, cacheSize = 0;
		}
	}
}());

function testIt(method) {
	var loopCount = 0;
	var maxLoops = 10000000;

	console.log((method?"STRING":"MOD") + " - creating " + maxLoops + " random numbers to see if they are magic");

	var start = new Date();
	while (loopCount<maxLoops) {
		magicNumberFinder.isMagic(Math.floor(Math.random()*maxLoops), method);
		loopCount++;
	}
	var end = new Date();

	magicNumberFinder.cacheStats(maxLoops);
	console.log("time taken (ms) : " + (end.getTime() - start.getTime()));
	console.log("------------------------------");
}

testIt();
magicNumberFinder.wipeCache();
testIt("s");
//console.log(magicNumberFinder.isMagic(22));