Elegance

Here's an example what 'elegance' means in programming. These are three solutions to a Project Euler problem.  All three programs do the same thing-find prime factors of a given number. (I've removed comments). The relative sizes of the scripts are 1.285kb, 0.694kb and 0.139kb respectively.

1)

var biggestPrimeFactor = 1;

var numberToFactor = 600851475143;

var factorArray = []

for (i = 2; i <= Math.sqrt(numberToFactor); i++) {

    if(numberToFactor % i === 0) {

        factorArray.push(i);

        var isPrime = true;

        for(j = 2; j <= Math.sqrt(i); j++) {

            if(i % j === 0) {

                var isPrime = false;

            }

        }

        if(isPrime === true) {

            biggestPrimeFactor = i;

        }

    }

}

for (factor in factorArray) {

    var bigFactor = numberToFactor / factorArray[factor];

    var isPrime = true

    for (i = 2; i <= Math.sqrt(bigFactor); i++)

        if(bigFactor % i === 0) {

            var isPrime = false;

        }

    if(isPrime === true) {

        biggestPrimeFactor = bigFactor;

    }

}

if(biggestPrimeFactor === 1) {

    biggestPrimeFactor = numberToFactor;

}

console.log(biggestPrimeFactor);

2)

var i=1;

var largest;

var numtofactor= 600851475143;  

var wholecheck;  

var remain;        

var factorcheck=1;  

while(factorcheck!==numtofactor){

    if(i%2===0)    {

i++;

}

else {  
           wholecheck=numtofactor/i;

remain = wholecheck-Math.floor(wholecheck); 

if(remain===0){

largest=i;

i++;

factorcheck=largest * factorcheck;

}

else {

i++;

}

}

                                                           }

console.log(largest);

3)

function solution3 (x) {

for(var i = 2; i < x; i++) {

if (x % i === 0) {

x /= i;

}

}

console.log(x);

}

solution3(600851475143);

This demonstrates a beautiful aspect of information: there are multiple paths to the same answer and there is often a way of achieving more with less. (Mine was the second script, I was proud of it until I found the third one.)