09. Login

function login (input) {

    let user = input[0];
    let pass = '';

    for (let i = user.length - 1; i >= 0; i--){
        pass += user[i];
    }

    for (let i = 1; i <= 4; i++) {

        if (pass === input[i]) {
            console.log(`User ${user} logged in.`);
            break;
        } else {
            if (i === 4) {
                console.log(`User ${user} blocked!`);
            } else {
                console.log('Incorrect password. Try again.');
            }
        }
    }
}


Адванс решение:

function login (input) {

    let user = input.shift();

    for (let i = 1; i <= 4; i++) {

        if (user === input.shift().split("").reverse().join("")) {
            console.log(`User ${user} logged in.`);
            break;
        } else {
            console.log(i === 4 ? `User ${user} blocked!` : 'Incorrect password. Try again.');
        }
    }
}