var database = [
    {
        username: "Rafnexx",
        password: "passw0rd"
    },
    {
        username: "admin",
        password: "haslo"
    },
    {
        username: "johny",
        password: "haslo"
    },
    {
        username: "mnemonic",
        password: "haslo"
    },
    {
        username: "tibia",
        password: "haslo"
    },

];

var newsfeed = [
    {
        username: "John",
        timeline: "I'm tired!"
    },
    {
        username: "Szymon",
        timeline: "That's so exciting!"
    },
    {
        username: "Patryk",
        timeline: "Tomorrow, I'll destroy you guys!"
    }
];

var userNamePrompt = prompt("What's your username?");
var passwordPrompt = prompt("What's your password?");
var correctUserData = false;

function checkingUserNameAndPassword(user, pass) {
    for(var i = 0; i <= database.length -1; i++){
        if( (user === database[i].username) && (pass === database[i].password) ) {
            correctUserData = true;
            break;
        }
        else {
            correctUserData = false;
        }
    }
}

checkingUserNameAndPassword(userNamePrompt, passwordPrompt);

function signingIn(status) {
    if( status === true ) {
        console.log(newsfeed);
    }
    else {
        console.log("Błędna nazwa użytkownika lub hasło!");
    }
}

signingIn(correctUserData);