Node.js

Question 1

What makes Node.js good as a runtime environment?

Answer 1

It is non-blocking, which means it can handle concurrent connections efficiently

Question 2

What does GET do, is it safe and can it be cached?

Answer 2

GET retrieves data from the server, it is safe as it does not have any side effects on the server and it can be cached

Question 3

What does POST do? Is it safe and is it cached?

Answer 3

Used to submit data to be processed by the server, it is not safe as it may have side effects of the server and they are not cached

Question 4

What does PUT do?

Answer 4

Used to update a resource on the server, it may require additional security considerations.

Question 5

What does PUT being idempotent entail?

Answer 5

Multiple identical requests will produce the same result as a single one

Question 6

Write

How to import the http module?

Answer 6

const http = require(“http”);

Question 7

Write

How to create a server?

Answer 7

const server = http.createServer();
server.listen(port);

server.listen(3000, () => {console.log(…);}); to check functionality

Question 8

Write

The configuration of a createServer()

Answer 8

const server = http.createServer((req, res) => {console.log(“res”)});

Question 9

Write

How to send response from server?

Answer 9

res.write(“Response”);

Question 10

Write

How to finish response?

Answer 10

res.end();

Question 11

How to send Header in server?

Answer 11

res.writeHead(200, {“Content type” : “text/plain”});

Question 12

What pieces can be parsed from the following URL:
http://site.com/path/?q=val#hash

Answer 12

In order:
site.com hostname
/path/ pathname
q=val query
#hash hash

Question 13

Write

How to implement routes for different HTTP methods? Write some statements accordingly

Answer 13

We use the req.method
if (req.method===”GET”){
res.writeHead(200, {“Content type” : “text/plain”});
res.end(“GET method used”);
}

Question 14

Write

The two required statements to parse request data

Answer 14

const url = require(“url”);
const querystring = require(“querystring”);

Question 15

Write

Given the required modules, how to parse a URL?

Answer 15

const parsedURL = url.parse(req.url);
const queryParams = querystring.parse(parsedURL.query);

Question 16

Write

How to import express.js

Answer 16

const express = require(“express”);
const app = express();

Question 17

Write

How to handle routes with express

Answer 17

const express = require(“express”);
const app = express();

app.post(“action”, (req, res) => {res.send(“…”);});

Question 18

Write

How to file I/O?

Answer 18

const fs = require(“fs”);
fs.writeFile(“fileToWriteTo.txt”, “Written Text”);
fs.readFile(“fileToReadFrom.txt”);

Question 19

What does path.join() do?

What module does it require?

Answer 19

It constructs a valid file path, from various parts of file paths.

const path = require(“path”), also requires express

Question 20

What is __dirname?

Answer 20

It represents the directory of the current module, where the script is located

Question 21

What does express.static? What does it do?

Answer 21

It is middleware employed to serve static files. It also makes files in the “public” directory static resources, meaning they are available to clients.

Question 22

Write

The statements required for static file handling (the required modules and the code)

Answer 22

const express = require(“express”);
const app = express();
const path = require(“path”);

app.use(express.static(path.join(__dirname, “public”)));

Question 23

What are cookies (simplest definition)?

Answer 23

Small pieces of data stored on the client’s browser.

Question 24

What is the purpose of cookies?

Answer 24

They store information that is accessible across different pages/sessions (user preferences, tracking user behavior, etc…)

Question 25

# Write How to implement the cookieParser?

Answer 25

const express = require("express"); const app = "express" const cookieParser = require("cookie-parser"); app.use(cookieParser());

Question 26

# Write How to set a cookie?

Answer 26

app.get("/set-cookie", (req, res) => { res.cookie("username", "Lud"); res.end("Cookie is set");});

Question 27

# Write How to read a cookie?

Answer 27

req.cookies.property

Question 28

What are sessions?

Answer 28

A mechanism for maintaining user state across multiple requests, they are stored on the server

Question 29

# Write How to use express-session middleware?

Answer 29

const express = require("express"); const session = require("express-session"); const app = express(); app.use(session({ secret: "your-secret-key";}));

Question 30

# Write How to set a session?

Answer 30

app.get("/set-session", (req, res) => { req.session.username("Dave"); res.send("username set");});

Question 31

# Write How to get a session?

Answer 31

app.get("/get-session", (req, res) => { const username = req.session.username; res.send("Hello, ${username}");});