Javascript Help - selfDividingNumbers Algorithm producing all 0's

Question

Greetings Stack Overflow!

First off, this is my first question!

I am trying to solve the selfDividingNumbers algorithm and I ran into this interesting problem. This function is supposed to take a range of numbers to check if they are self dividing.

Self Dividing example:

128 is a self-dividing number because 

128 % 1 == 0, 128 % 2 == 0, and 128 % 8 == 0.

My attempt with Javascript.

/*      
   selfDividingNumbers( 1, 22 );
*/

var selfDividingNumbers = function(left, right) {
    var output = [];
    while(left <= right){
        // convert number into an array of strings, size 1
        var leftString = left.toString().split();

        // initialize digit iterator
        var currentDigit = leftString[0]; 
        
        for(var i = 0; i < leftString.length; i++){
            currentDigit = parseInt(leftString[i])
            console.log( left % currentDigit );
        }
    
        // increment lower bound
        left++;
    }

    return output
};

When comparing the current lower bound to the current digit of the lower bound, left % currentDigit it always produces zero! I figure this is probably a type error but I am unsure of why and would love for someone to point out why!

Would also like to see any other ideas to avoid this problem!

I figured this was a good chance to get a better handle on Javascript considering I am clueless as to why my program is producing this output. Any help would be appreciated! :)

Thanks Stack Overflow!

Answer 1

Calling split() isn't buying you anything. Remove it and you'll get the results you expect. You still have to write the code to populate output though.

Answer 2

The answer by @Joseph may fix your current code, but I think there is a potentially easier way to go about doing this. Consider the following script:

var start = 128;
var num = start;
var sd = true;

while (num > 0) {
    var last = num % 10;
    if (start % last != 0) {
        sd = false;
        break;
    }
    num = Math.floor(num / 10);
}

if (sd) {
    print("Is self dividing");
}
else {
    print("Is NOT self dividing");
}

Demo

To test each digit in the number for its ability to cleanly divide the original number, you can simply use a loop. In each iteration, check num % 10 to get the current digit, and then divide the number by ten. If we never see a digit which can not divide evenly, then the number is not self dividing, otherwise it is.