I am learning node.js and express and am working through some examples from Brad Dayleys book. I have copied the code below from the book, which implements some basic session authentication using crypto and express-session:

var express = require('express');
var bodyParser = require('body-parser');
var cookieParser = require('cookie-parser');
var session = require('express-session');
var crypto = require('crypto');   


//encrypt password function
function hashPW(pwd) {
    var hash = crypto.createHash('sha256').update(pwd).digest('base64');
    return hash.toString();
}

var app = express();

//this is the new way to call this module
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
    extended: true
}));
app.use(cookieParser('MAGICString'));

//new way to init session
app.use(session({secret: 'ssshhhhh', resave: false, saveUninitialized: false}));

//see if user is authorized to be here
app.get('/restricted', function(req, res) {
    if (req.session.user) {
        res.send ('<h2>' + req.session.success + '</h2>' +
                '<p>You have entered the restricted section<p><br>' +
                '<a href="/logout">logout</a>');
    }
    else {
        req.session.error = 'Access denied';
        res.redirect('/login');
    }
});

app.get('/logout', function (req, res) {
    req.session.destroy(function() {
        res.redirect('/login');
    });
});

app.get('/login', function(req, res) {
    var response = '<form method="POST">' +
            'Username: <input type="text" name="username"><br>' +
            'Password: <input type="text" name="password"><br>' +
            '<input type="submit" value="Submit"></form>';

    if (req.session.user) {
        res.redirect('/restricted');
    } else if (req.session.error) {
            response += '<h2>' + req.session.error + '</h2>';
        }

    res.type = ('html');
    res.send(response);
});


//on form submit
app.post('/login', function (req, res) {
    //user should be a lookup of req.body.username in database
    var user = {name: req.body.username, password:hashPW("myPass")};
    if (user.password === hashPW(req.body.password.toString())) {
        req.session.regenerate(function() {
            req.session.user = user;
            req.session.success = 'Authenticated as ' + user.name;
            res.redirect('/restricted');
        });
    } else {
        req.session.regenerate(function() {
            req.session.error = 'Authentication failed';
            res.redirect('/restricted');
        });
        res.redirect('/login');
    }
});

app.listen(8080);

When I run I get the error:

TypeError: Property 'type' of object #<ServerResponse> is not a function
   at ServerResponse.send (/home/terry/myProjects/serverLearn/node_modules/express/lib/response.js:129:14)
   at app.post.user.name (/home/terry/myProjects/serverLearn/express_auth_session.js:63:9)
   at Layer.handle [as handle_request] (/home/terry/myProjects/serverLearn/node_modules/express/lib/router/layer.js:82:5)
   at next (/home/terry/myProjects/serverLearn/node_modules/express/lib/router/route.js:110:13)
   at Route.dispatch (/home/terry/myProjects/serverLearn/node_modules/express/lib/router/route.js:91:3)
   at Layer.handle [as handle_request] (/home/terry/myProjects/serverLearn/node_modules/express/lib/router/layer.js:82:5)
   at /home/terry/myProjects/serverLearn/node_modules/express/lib/router/index.js:267:22
   at Function.proto.process_params (/home/terry/myProjects/serverLearn/node_modules/express/lib/router/index.js:321:12)
   at next (/home/terry/myProjects/serverLearn/node_modules/express/lib/router/index.js:261:10)
   at Object.<anonymous> (/home/terry/myProjects/serverLearn/node_modules/express-session/index.js:421:7)


   

Forgive my noobness, but I just can't see what is wrong. I can't even tell where exactly it has the error. Any help or pointers would be greatly appreciated!