Largest palindrome product

largest_palindrome_product.js

function getPalindromes(from, to) {
    var palindromes = [];
    for (var n = from; n <= to; n++) {
        if (isPalindrome(n)) palindromes.push(n);
    }
    return palindromes;
}
function isPalindrome(n) {
    var nCArray = n.toString().split('');
    for (var i = 0; i < nCArray.length; i++) {
        if (nCArray[i] != nCArray[nCArray.length - 1 - i]) return false;
    }
    return true;
}
function getMaxPalindromeWith2KDigitFactors(k) {
    var low = parseInt("1" + Array.apply(null, Array(k - 1)).map(function (_, i) { return "0"; }).join(''));
    var high = parseInt("9" + Array.apply(null, Array(k - 1)).map(function (_, i) { return "9"; }).join(''));

    var palindromes = getPalindromes(Math.pow(low,2), Math.pow(high,2));

    var kDigitNumbers = Array.apply(null, Array(high - low + 1)).map(function(_, i) { return low + i; });
    
    var candidates = [];
    for (var pi = 0; pi < kDigitNumbers.length; pi++) {
        for (var pj = 0; pj < kDigitNumbers.length; pj++) {
            var n = kDigitNumbers[pi] * kDigitNumbers[pj];
            if (palindromes.indexOf(n) >= 0) {
                candidates.push(n);
            }
        }
    }
    return Math.max.apply(null, candidates);
}

function test(actual, expected, err) {
    if (actual.constructor === Array && expected.constructor === Array) {
        if (actual.length === expected.length && 
            actual.every(function (e, i) {
                return e === expected[i];
        })) console.log("SUCCESS");
        else err(actual, expected);
    }
    else if (actual === expected) console.log("SUCCESS");
    else err(actual, expected);
}

function errMsg(actual, expected) {
    console.error("ERROR. Found: " + actual + " but expected: " + expected);
}

test(getMaxPalindromeWith2KDigitFactors(3), 906609, errMsg);

project euler problem 4