Question

Working on a project, I have this issue where my array “slicetable” returns undefined every time, and I do not know how to solve this problem. I have a function that generates an array of likelihoods for cryptographic key lengths – I then need to split the text into individual strings of n-th keys, up to the length of the “key”. I’ve worked for the last 4 hours on this problem, and don’t know where to begin. If anyone could recommend a good strategy for tackling problems like this, as well as helping me out on this one, that would be great – I’m still quite new to all of this.

function vigenerekey(text, max) {
    // Standardize the text
    text = text.split(" ").join("").toUpperCase();
    // Obtain our list of key length probabilities
    var probabilities = vigenerekeylength(text, max);
    // Extend the Math.max to arrays
    Array.max = function(array){
        return Math.max.apply(Math, array);
    };

    // Find the position of the most probable key length
    for (var d = 0; d <=12; d++) {
        if (probabilities[d] === probabilities.max) {
            return;
        }
    }
    // Slice the text into [d] parts (the length of the key)
    var slicetable = ['','','','','','','','','','','','','','','','','','','','',''];
    var chiresults = [];
    for (var e = 0; e <= d; e++){
        for (f = 0; f <= text.length; f++) {
            if (f % e === 0) {
                slicetable[e] += text.charAt(f);        
            }
        }
    return slicetable;
    }

}

Answer 1

Don’t you mean this: (break instead of return)

// Find the position of the most probable key length 
for (var d = 0; d <=12; d++) { 
    if (probabilities[d] === probabilities.max) { 
        break;
    } 
}