password-handler/index.js

Check password strength and generate strong password

function calculateScore(password) {
    let score = 0;
    if (password.length > 8) {
        if (password.length > 16) {
            score += 2;
        } else {
            score += 1;
        }
    }
    if (/[a-z]/.test(password)) {
        score += 1;
    }
    if (/[A-Z]/.test(password)) {
        score += 1;
    }
    if (/[0-9]/.test(password)) {
        score += 1;
    }
    if (/[!@#$%^&*()_+\-=[\]{};':"\\|,.<>/?]/.test(password)) {
        score += 2;
    }
    return score;
}

function checkCommonPasswords(password) {
    const commonPasswords = [
        "password",
        "123456",
        "12345678",
        "123456789",
        "qwerty",
        "12345",
        "1234567890",
        "1234567",
        "111111",
        "123123",
        "iloveyou",
        "1q2w3e4r",
        "123qwe",
        "654321",
        "123qaz",
        "Hello123",
        "user",
        "admin",
        "********",
        "admin123",
        "000000",
        "12345678910",
        "UNKNOWN",
    ];
    if (commonPasswords.includes(password)) {
        return true;
    }
    return false;
}

function generateRandomIndex(min = 0, max = 10) {
    return Math.floor(Math.random() * (max - min) + min);
}
function makeStrongPassword(password) {
    const lowercase = "abcdefghijklmnopqrstuvwxyz";
    const uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    const numbers = "0123456789";
    const symbols = "!@#$%^&*()_+-";
    if (!password) {
        for (let i = 0; i < 10; i++) {
            let lchars = lowercase[generateRandomIndex(0, lowercase.length)];
            let uchars = uppercase[generateRandomIndex(0, uppercase.length)];
            let nchars = numbers[generateRandomIndex(0, numbers.length)];
            let schars = symbols[generateRandomIndex(0, symbols.length)];
            let chars = [lchars, uchars, nchars, schars];

            let idx1 = generateRandomIndex(0, password.length);
            let idx2 = generateRandomIndex(0, password.length);
            let idx3 = generateRandomIndex(0, password.length);

            let charsIdx1 = chars[generateRandomIndex(0, chars.length)];
            let charsIdx2 = chars[generateRandomIndex(0, chars.length)];

            password =
                password.substring(0, idx1) +
                charsIdx1 +
                password.substring(idx1, idx2) +
                charsIdx2 +
                password.substring(idx2, idx3) +
                charsIdx1 +
                password.substring(idx3, password.length) +
                charsIdx2;
        }
        return password;
    }

    for (let i = password.length; i < 10; i++) {
        let lchars = lowercase[generateRandomIndex(0, lowercase.length)];
        let uchars = uppercase[generateRandomIndex(0, uppercase.length)];
        let nchars = numbers[generateRandomIndex(0, numbers.length)];
        let schars = symbols[generateRandomIndex(0, symbols.length)];
        let chars = [lchars, uchars, nchars, schars];
        let charsIdx = Math.floor(generateRandomIndex(0, chars.length) % 11);
        let passIdx = generateRandomIndex(0, password.length);

        password =
            password.slice(0, passIdx) +
            chars[charsIdx] +
            lchars +
            uchars +
            nchars +
            schars +
            password.slice(passIdx);
    }
    return password;
}

function checkPasswordStrength(password) {
    let nouns = [
        "nephew",
        "niece",
        "child",
        "son",
        "daughter",
        "grandson",
        "granddaughter",
    ];
    let strength = {};
    let reason = [];

    if (checkCommonPasswords(password)) {
        strength.message = `Are you kidding me? Your password is ${password}. My new born ${
            nouns[generateRandomIndex(0, nouns.length)]
        } can create bettter password!`;
        reason.push("Password is too common");
    }

    const minLength = 8;
    if (password.length < minLength) {
        reason.push(`Password must be at least ${minLength} characters`);
    }
    const hasUppercase = /[A-Z]/.test(password);
    const hasLowercase = /[a-z]/.test(password);
    const hasNumber = /[0-9]/.test(password);
    const hasSpecialChar = /[^A-Za-z0-9]/.test(password);

    if (!hasUppercase) {
        reason.push("Password must contain at least one uppercase letter");
    }
    if (!hasLowercase) {
        reason.push("Password must contain at least one lowercase letter");
    }
    if (!hasNumber) {
        reason.push("Password must contain at least one number");
    }
    if (!hasSpecialChar) {
        reason.push("Password must contain at least one special character");
    }

    strength.score = calculateScore(password);

    if (strength.score === 7) {
        strength.strength = "Perfecto 😙👌";
    } else if (strength.score === 6) {
        strength.strength = "Well done 😎";
        if (reason.length > 0) {
            strength.reason = reason;
        }
    } else if (strength.score === 5) {
        strength.strength = "Strong";
        if (reason.length > 0) {
            strength.reason = reason;
        }
    } else if (strength.score >= 3) {
        strength.strength = "All right";
        if (reason.length > 0) {
            strength.reason = reason;
        }
    } else if (strength.score > 1) {
        strength.strength = "Medium";
        if (reason.length > 0) {
            strength.reason = reason;
        }
    } else if (strength.score === 1) {
        strength.strength = "Weak";
        if (reason.length > 0) {
            strength.reason = reason;
        }
    } else {
        strength.strength = "Very weak";
        strength.reason = reason;
    }
    return strength;
}

module.exports = {
    checkPasswordStrength,
    makeStrongPassword,
};