AUTH_TOKEN

Your authentication token that you acquired after a successful login.

GMAIL_EMAIL

Your email on Gmail that will be used to send confirmation emails.

OAUTH_CLIENT_ID

Your client id that we explained in the Secure Emails lesson.

OAUTH_CLIENT_SECRET

Your client's secret that we explained in the Secure Emails lesson.

OAUTH_REFRESH_TOKEN

Your refresh token that we explained in the Secure Emails lesson.

docker.tar.gz

PORT

CONFIRMATION_SECRET_KEY

CRYPTO_ALGORITHM

INITIALIZATION_VECTOR

MONGO_URI

SALT

TOKEN_SECRET_KEY

hello_world

wrong_hello_world

routes_examples

events

async

mongoose

usermodel

signup

confirmation

login

auth

props

router

react

SignupGUI

ConfirmationGUI

LoginGUI

AuthGUI

navbar

SignupPage

SignupPageGUI

ConfirmationPage

LoginPage

ux-page

home-page

UploadGUI

SpellGUI

ImageGUI

GetGUI

UpdateGUI

DeleteGUI

CRUD

Heroku

GetGUI-copy

SpellGUIV2

ImageGUIV2

CRUDV2

Node.js is a popular JavaScript runtime environment used to create server-side applications. It is an ideal tool for building robust, full-stack web applications with React.

This course is an introduction to web development leveraging these two popular technologies. You’ll learn server-side applications with Node.js and learn to add database functionality with MongoDB fitting into the Express application framework. You’ll then build a user authorization system using the JSON Web Token (JWT).

You’ll then focus on a client-side environment built with React. You’ll build a sample application to get familiar with the framework before styling the application and adding necessary user-interaction elements. You’ll wrap up by tying the frontend and backend together and deploying your web application with Heroku.

By the end of this course, you’ll be prepared to build real-world websites using the most popular JavaScript tools.

Building Full-Stack Web Applications With Node.js and React

It appends to the file synchronously and print `Saved!` in the console.

It appends to the file asynchronously and print `Saved!` in the console.

What happens when the following code is executed?

```
const fs = require('fs');

fs.appendFile('educative.txt', 'data to append', function (err) {
  if (err) throw err;
  console.log('Saved!');
});
```

What happens when the following code is executed?
<pre><code>const fs = require('fs');

fs.appendFile('educative.txt', 'data to append', function (err) {
 if (err) throw err;
 console.log('Saved!');
});
</code></pre>

Promises are used to handle the asynchronous result of an operation, while async/await is used to block code execution.

Promises are used to block code execution, while async/await is used to handle the asynchronous result of an operation.

They perform the same function. Both of them block code execution. Async/await is just syntax sugar for promises.

They perform the same function. Both of them handle the asynchronous result of an operation. Async/await is just syntax sugar for promises.

What are the differences between promises and async/await?

What are the differences between promises and async/await?

```
const http = require("http");
http.createServer(function (request, response) {
  response.writeHead(200, {'Content-Type': 'text/plain'});
  response.end('Hello World\n');
}).listen(3000);
```

```
const http = require("http");
http.createServer(function (request, response) {
  response.writeHead(500, {'Content-Type': 'text/plain'});
  response.end('Hello World\n');
}).listen(3000);
```

```
const http = require("http");
http.createServer(function (request, response) {
  response.writeHead(200, {'Content-Type': 'text/plain'});
  response.end('Hello World\n');
}).listen(5000);
```

```
const http = require("http");
http.createServer(function (request, response) {
  response.writeHead(200, {'Content-Type': 'text/plain'});
}).listen(3000);
```

**(Select all that apply.)** How do we create a server in Node.js that returns a `Hello World` message? 

(Select all that apply.) How do we create a server in Node.js that returns a <code>Hello World</code> message?

Which function argument below is available to route handlers in Express?

Which function argument below is available to route handlers in Express?

The `package.json` file is the core of the Node.js application.

The `package.json` file can be replaced at any location in the project directory.

The npm init command is used to create the `package.json` file.

The parameters of the `package.json` file can be edited manually.

**(Select all that apply.)** Which of the following is true about the `package.json` file? 

(Select all that apply.) Which of the following is true about the <code>package.json</code> file?

`db.books.findOne( { "userId": { $lt: 42 }})`

`db.books.find( { "userId": { $lt: 42 }})`

`db.books.retrieve( { "userId": { $lt: 42 }})`

Which query below selects documents in the `books` collection that has a userId less than 34?

Which query below selects documents in the <code>books</code> collection that has a userId less than 34?

Which operator below can be used to control the number of items in an array returned from a query?

Which operator below can be used to control the number of items in an array returned from a query?

limit, skip, sort
```
db.students.find({}).limit(150).skip(100).sort()
```

sort, limit, skip
```
db.students.find({}).sort().limit(150).skip(100)
```

```
db.students.find({}).limit(150).sort().skip(100)
```

```
db.students.find({}).sort().skip(100).limit(50)
```

Which operation below can be used to retrieve the third set of 50 documents from a sorted collection that has millions of student records?

Which operation below can be used to retrieve the third set of 50 documents from a sorted collection that has millions of student records?

```
2  Listener(s) listening to connection event
I am listener1.
I am listener2.
I am listener1.
I am listener2.
1 Listner(s) listening to connection event
Thank you, buy.
```

```
2 Listener(s) listening to connection event
I am listener1.
I am listener2.
I am listener1.
I am listener2.
2 Listener(s) listening to connection event
Thank you, bye.
```

```
2 Listener(s) listening to connection event
I am listener1.
I am listener2.
Listener1 removed.
I am listener2.
1 Listener(s) listening to connection event
Thank you, bye.
```

```
2 Listener(s) listening to connection event
I am listener1.
I am listener2.
Listener1 removed.
I am listener1.
1 Listener(s) listening to connection event
Thank you, bye.
```

What is the output of the following code?
```
let events = require('events');
let eventEmitter = new events.EventEmitter();

let listener1 = function listener1() {
   console.log('I am listener1');
}

let listener2 = function listener2() {
   console.log('I am listener2');
}

eventEmitter.addListener('connection', listener2);

eventEmitter.on('connection', listner2);

let eventListeners = require('events').EventEmitter.listenerCount
   (eventEmitter,'connection');
console.log(eventListeners + " Listener(s) listening to connection event");


eventEmitter.emit('connection');


eventEmitter.removeListener('connection', listener1);
console.log("Listener1 removed");


eventEmitter.emit('connection');

eventListeners = require('events').EventEmitter.listenerCount(eventEmitter,'connection');
console.log(eventListeners + " Listener(s) listening to connection event");

console.log("Thank you, bye.");

```

What is the output of the following code?
<pre><code>let events = require('events');
let eventEmitter = new events.EventEmitter();

let listener1 = function listener1() {
 console.log('I am listener1');
}

let listener2 = function listener2() {
 console.log('I am listener2');
}

eventEmitter.addListener('connection', listener2);

eventEmitter.on('connection', listner2);

let eventListeners = require('events').EventEmitter.listenerCount
 (eventEmitter,'connection');
console.log(eventListeners + &quot; Listener(s) listening to connection event&quot;);


eventEmitter.emit('connection');


eventEmitter.removeListener('connection', listener1);
console.log(&quot;Listener1 removed&quot;);


eventEmitter.emit('connection');

eventListeners = require('events').EventEmitter.listenerCount(eventEmitter,'connection');
console.log(eventListeners + &quot; Listener(s) listening to connection event&quot;);

console.log(&quot;Thank you, bye.&quot;);

</code></pre>

What will the following route match?
```
app.get('/us+er', function (req, res) {
  res.send('us+er')
})
```

What will the following route match?
<pre><code>app.get('/us+er', function (req, res) {
 res.send('us+er')
})
</code></pre>

Choose the correct answer(s)

Choose the correct answer(s)

Test your knowledge of Node.js, Express, and MongoDB.

Before You Begin

The Server-side

User Authentication with a JSON Web Token

Set up the Client-side Environment

Develop the Client-side

Business Logic

Server-side Routes

Client-side Routes

Appendix

Conclusion

Test Yourself: Server-side Architecture