bitch

//server.js

app.post("/signin", function(request, response) {

    // Only run logIn function if the user is not currently logged in
    if (!response.locals.user) {

        // Log the user in and then set the session cookie
        userData.logIn(request.body.username, request.body.password).then(function(sessionID) {
            if (sessionID) {
                // If the user was successfully signed in, create a new cookie with the generated sessionID
                var expiresAt = new Date();
                expiresAt.setHours(expiresAt.getHours() + 5);

                response.cookie("sessionID", sessionID, { expires: expiresAt });
                //console.log("Created new sessionID cookie: {sessionID: " + sessionID + "}");

                response.json({status: "success"});
            }
        }, function(errorMessage) {
            response.status(500).json({ error: errorMessage });
        });

    } else {
        reponse.status(500).json({error: "User already signed in."})
    }

});

//data.js

exports.logIn = function (username, password) {

            // Error checking
            if (!username || !password) {
                return Promise.reject("You must provide both a username and password.");
            } else if (typeof username !== 'string' || typeof password !== 'string') {
                return Promise.reject("Arguments not correct type.");
            }

            return usersCollection.find({"username": username}).limit(1).toArray().then(function(listOfUsers) {
                // If user exists, check password
                if (listOfUsers.length !== 0) {
                    var user = listOfUsers[0];

                    // Compare hash of given password to hash in the db
                    if (bcrypt.compareSync(password, user.encryptedPassword)) {
                        // Create a new session ID for the user and update the user in the database
                        var sessionID = Guid.create().toString();

                        return usersCollection.update({"username": username}, {$set: {"currentSessionId": sessionID}}).then(function() {
                            return Promise.resolve(sessionID);
                        });
                    } else {
                        return Promise.reject("Incorrect password.");
                    }

                } else {
                    return Promise.reject("A user with that username does not exist.");
                }
            });
        };

//Client Slide

<h1>Sign In</h1>
<form id="signInForm">
    <label>username: <input name="username" placeholder="Username" type="text"></label>
    <br />
    <label>password: <input name="password" placeholder="Password" type="password"></label>
    <br />
    <input type="submit" value="Sign In">
</form>

<script>
    $('#signInForm').on('submit', function(e) {

            $.ajax({
                url: '/signin',
                type: 'POST',
                data: {
                    'username': $('#signInForm input[name="username"]').val(),
                    'password': $('#signInForm input[name="password"]').val()
                },
                success: function(data) {
                    location.reload();
                },
                error: function(xhr, status, error) {
                    alert(xhr.responseText + ' (' + xhr.status + ')');
                }
            });

            return false;
        });
</script>