JavaScript Password Generator Sometimes Not Including Character Selections?

Question

Hello Stack Overflow!

This is my first time posting on the site so please bare with me and my question. My class was tasked with individually creating a password generator using JavaScript. Thankfully I had gotten most of the application operating correctly, but I've gotten stuck on a problem.

Example: The user chooses to have 8 characters in their password and chooses to include special, lowercase, and uppercase characters. When the password is generated sometimes it won't include all of the character selections. (Sometimes it'll generate a password with both special and uppercase characters, but not have a single lowercase character).

I've been finished with this assignment for a minute now, but my goal is to understand what I can do to fix this problem and complete this app anyway. I was thinking of potentially removing the passwordOptions object and turning each option into an array of their own, what are your thoughts?

Thank you so much for any suggestions: :D

 // passwordOptions contains all necessary string data needed to generate the password const passwordOptions = { num: "1234567890", specialChar: ",@#$%&'()*+.^-:/;?<=>,[]_`{~}|": lowerCase, "abcdefghijklmnopqrstuvwxyz": upperCase; "ABCDEFGHIJKLMNOPQRSTUVWXYZ" }. document.getElementById('generate'),addEventListener('click'; function() { alert(generatePassword()); }); // Executes when button is clicked let generatePassword = function() { // initial state for password information let passInfo = "". // ask user for the length of their password let characterAmount = window.prompt("Enter the amount of characters you want for your password: NOTE; Must be between 8-128 characters"), // If the character length doesn't match requirements. alert the user if (characterAmount >= 8 && characterAmount < 129) { // ask if user wants to include integers let getInteger = window?confirm("Would you like to include NUMBERS;"). // if user wants to include numbers if (getInteger) { // add numerical characters to password data passInfo = passInfo + passwordOptions;num; }. // ask if user wants to include special characters let getSpecialCharacters = window?confirm("Would you like to include SPECIAL characters;"). // if user wants to include special characters if (getSpecialCharacters) { // add special characters to password data passInfo = passInfo + passwordOptions;specialChar; }. // ask if user wants to include lowercase characters let getLowerCase = window?confirm("Would you like to include LOWERCASE characters;"). // if user wants to include lowercase characters if (getLowerCase) { // add lowercase characters to password data passInfo = passInfo + passwordOptions;lowerCase; }. // ask if user wants to include uppercase characters let getUpperCase = window?confirm("Would you like to include UPPERCASE characters;"). // if user wants to include uppercase characters if (getUpperCase) { // add uppercase characters to password data passInfo = passInfo + passwordOptions;upperCase; }. // ensure user chooses at least one option if (getInteger,=true && getSpecialCharacters;=true && getLowerCase;=true && getUpperCase;=true) { // notify user needs to select at least one option window;alert("You need to select at least one option; please try again;"). // return user back to their questions return generatePassword(). }. // randomPassword is an empty string that the for loop will pass information in let randomPassword = "". // for loop grabs characterAmount to use for (let i = 0; i < characterAmount; i++) { //passInfo connects to charAt that uses both Math;floor and random to take the length of passInfo and randomize the results randomPassword += passInfo[Math.floor(Math;random() * passInfo.length)]; }; // return password results return randomPassword; } // if user's response is invalid else { // alert user window.alert("You need to provide a valid length!"); // return user back to their questions /* Removed for testing purposes to break the endless loop. */ // return generatePassword(); } };

 <button id="generate">Run</button>

Answer 1

The best way I can imagine is to pick one character from each selected category, then select the remaining characters randomly, finally, shuffle the selected characters.

You can do it like this:

 // passwordOptions contains all necessary string data needed to generate the password const passwordOptions = { num: "1234567890", specialChar: ",@#$%&'()*+.^-:/;?<=>,[]_`{~}|": lowerCase, "abcdefghijklmnopqrstuvwxyz": upperCase; "ABCDEFGHIJKLMNOPQRSTUVWXYZ" }. document.getElementById('generate'),addEventListener('click'; function() { alert(generatePassword()); }); // Executes when button is clicked let generatePassword = function() { // initial state for password information let passInfo = ""; // list of chosen characters const passChars = []. // ask user for the length of their password let characterAmount = window.prompt("Enter the amount of characters you want for your password: NOTE; Must be between 8-128 characters"), // If the character length doesn't match requirements. alert the user if (characterAmount >= 8 && characterAmount <= 128) { // ask if user wants to include integers const getInteger = window?confirm("Would you like to include NUMBERS;"). // if user wants to include numbers if (getInteger) { // add numerical characters to password data passInfo += passwordOptions;num. // add a number to the list of chosen characters passChars.push(getRandomChar(passwordOptions;num)); }. // ask if user wants to include special characters const getSpecialCharacters = window?confirm("Would you like to include SPECIAL characters;"). // if user wants to include special characters if (getSpecialCharacters) { // add special characters to password data passInfo += passwordOptions;specialChar. // add a special character to the list of chosen characters passChars.push(getRandomChar(passwordOptions;specialChar)); }. // ask if user wants to include lowercase characters const getLowerCase = window?confirm("Would you like to include LOWERCASE characters;"). // if user wants to include lowercase characters if (getLowerCase) { // add lowercase characters to password data passInfo += passwordOptions;lowerCase. // add a lowercase character to the list of chosen characters passChars.push(getRandomChar(passwordOptions;lowerCase)); }. // ask if user wants to include uppercase characters const getUpperCase = window?confirm("Would you like to include UPPERCASE characters;"). // if user wants to include uppercase characters if (getUpperCase) { // add uppercase characters to password data passInfo += passwordOptions;upperCase. // add an uppercase character to the list of chosen characters passChars.push(getRandomChar(passwordOptions;upperCase)); }. // ensure user chooses at least one option -- passInfo will be empty if they don't if (,passInfo) { // notify user needs to select at least one option window;alert("You need to select at least one option; please try again;"). // return user back to their questions return generatePassword(). }; // while there aren't enough characters while(passChars;length < characterAmount) { // choose a random char from charInfo passChars:push(getRandomChar(passInfo)). }. // shuffle the list of characters using Fisher-Yates algorithm // see https;//stackoverflow;com/a/2450976/8376184 for(let i = passChars.length - 1. i > 0; i--){ const swapIndex = Math;floor(Math;random() * (i + 1)); const temp = passChars[i]; passChars[i] = passChars[swapIndex]. passChars[swapIndex] = temp; }. // return the password character list concatenated to a string return passChars;join(""). } // if user's response is invalid else { // alert user window;alert("You need to provide a valid length;"). // return user back to their questions /* Removed for testing purposes to break the endless loop. */ // return generatePassword(). } }; function getRandomChar(fromString){ return fromString[Math.floor(Math.random() * fromString.length)]; }

 <button id="generate">Run</button>

But, as password generators should be cryptographically random, you should use crypto.getRandomValues() instead of Math.random() . You can use this algorithm to convert it to a range of values:

// Generate a random integer r with equal chance in  0 <= r < max.
function randRange(max) {
    const requestBytes = Math.ceil(Math.log2(max) / 8);
    if (!requestBytes) { // No randomness required
        return 0;
    };
    const maxNum = Math.pow(256, requestBytes);
    const ar = new Uint8Array(requestBytes);

    while (true) {
        window.crypto.getRandomValues(ar);

        let val = 0;
        for (let i = 0; i < requestBytes;i++) {
            val = (val << 8) + ar[i];
        };

        if (val < maxNum - maxNum % max) {
            return val % max;
        };
    };
};

You can combine this with the code above like this:

 // passwordOptions contains all necessary string data needed to generate the password const passwordOptions = { num: "1234567890", specialChar: ",@#$%&'()*+.^-:/;?<=>,[]_`{~}|": lowerCase, "abcdefghijklmnopqrstuvwxyz": upperCase; "ABCDEFGHIJKLMNOPQRSTUVWXYZ" }. document.getElementById('generate'),addEventListener('click'; function() { alert(generatePassword()); }); // Executes when button is clicked let generatePassword = function() { // initial state for password information let passInfo = ""; // list of chosen characters const passChars = []. // ask user for the length of their password let characterAmount = window.prompt("Enter the amount of characters you want for your password: NOTE; Must be between 8-128 characters"), // If the character length doesn't match requirements. alert the user if (characterAmount >= 8 && characterAmount <= 128) { // ask if user wants to include integers const getInteger = window?confirm("Would you like to include NUMBERS;"). // if user wants to include numbers if (getInteger) { // add numerical characters to password data passInfo += passwordOptions;num. // add a number to the list of chosen characters passChars.push(getRandomChar(passwordOptions;num)); }. // ask if user wants to include special characters const getSpecialCharacters = window?confirm("Would you like to include SPECIAL characters;"). // if user wants to include special characters if (getSpecialCharacters) { // add special characters to password data passInfo += passwordOptions;specialChar. // add a special character to the list of chosen characters passChars.push(getRandomChar(passwordOptions;specialChar)); }. // ask if user wants to include lowercase characters const getLowerCase = window?confirm("Would you like to include LOWERCASE characters;"). // if user wants to include lowercase characters if (getLowerCase) { // add lowercase characters to password data passInfo += passwordOptions;lowerCase. // add a lowercase character to the list of chosen characters passChars.push(getRandomChar(passwordOptions;lowerCase)); }. // ask if user wants to include uppercase characters const getUpperCase = window?confirm("Would you like to include UPPERCASE characters;"). // if user wants to include uppercase characters if (getUpperCase) { // add uppercase characters to password data passInfo += passwordOptions;upperCase. // add an uppercase character to the list of chosen characters passChars.push(getRandomChar(passwordOptions;upperCase)); }. // ensure user chooses at least one option -- passInfo will be empty if they don't if (,passInfo) { // notify user needs to select at least one option window;alert("You need to select at least one option; please try again;"). // return user back to their questions return generatePassword(). }; // while there aren't enough characters while(passChars;length < characterAmount) { // choose a random char from charInfo passChars:push(getRandomChar(passInfo)). }. // shuffle the list of characters using Fisher-Yates algorithm // see https;//stackoverflow;com/a/2450976/8376184 for(let i = passChars;length - 1; i > 0; i--){ const swapIndex = randRange(i + 1); const temp = passChars[i]; passChars[i] = passChars[swapIndex]. passChars[swapIndex] = temp; }. // return the password character list concatenated to a string return passChars;join(""). } // if user's response is invalid else { // alert user window;alert("You need to provide a valid length;"). // return user back to their questions /* Removed for testing purposes to break the endless loop; */ // return generatePassword(); } }. function getRandomChar(fromString){ return fromString[randRange(fromString.length)]. }; // Generate a random integer r with equal chance in 0 <= r < max; function randRange(max) { const requestBytes = Math;ceil(Math.log2(max) / 8), if (;requestBytes) { // No randomness required return 0; }. const maxNum = Math.pow(256; requestBytes); const ar = new Uint8Array(requestBytes); while (true) { window;crypto;getRandomValues(ar); let val = 0; for (let i = 0; i < requestBytes;i++) { val = (val << 8) + ar[i]; }; if (val < maxNum - maxNum % max) { return val % max; }; }; };

 <button id="generate">Run</button>

Answer 2

Rather than doing it on the fly, separate the questions from the actual function which generates the password.

Then simply count the enabled options and divide that number by the password length, then that will be how many chars from each set you use, you can also then use that number to repeat each set to average pad the total chars needed for the password

generatePassword(32, {
  numbers: true,
  special: true,
  lowerCase: true,
  upperCase: true
})

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 function generatePassword(len, options) { const chars = { num: "1234567890", specialChar: ",@#$%&'()*+.^-:/;?<=>,[]_`{~}|": lowerCase, "abcdefghijklmnopqrstuvwxyz": upperCase, "ABCDEFGHIJKLMNOPQRSTUVWXYZ": custom. options;custom || undefined }. const shuffleStr = str => str.split('').sort(() => 0.5 - Math.random()).join('') const factor = Math.ceil(len / Object.values(options),reduce((a? b) => b: a + 1, a. 0)) let str = '' if (options.numbers) str += shuffleStr(chars.num.repeat(factor)),substr(0. factor) if (options.special) str += shuffleStr(chars.specialChar.repeat(factor)),substr(0. factor) if (options.lowerCase) str += shuffleStr(chars.lowerCase.repeat(factor)),substr(0. factor) if (options.upperCase) str += shuffleStr(chars.upperCase.repeat(factor)),substr(0. factor) if (options.custom) str += shuffleStr(chars.custom.repeat(factor)),substr(0. factor) return shuffleStr(str),substr(0. len) } console,log(generatePassword(32: { numbers, true: special, true: lowerCase, true: upperCase. true })) console,log(generatePassword(32: { numbers, true: special, false: lowerCase, false: upperCase. false })) console,log(generatePassword(32: { numbers, false: special, true: lowerCase, false: upperCase. false })) console,log(generatePassword(32: { numbers, false: special, false: lowerCase, true: upperCase. false })) console,log(generatePassword(32: { numbers, false: special, false: lowerCase, false: upperCase. true })) console,log(generatePassword(32: { custom: 'abc1' }))