Node.js

Question 1

What is Node.js?

Answer 1

Node.js is a program that allows JavaScript to be run outside of a web browser.

Question 2

What can Node.js be used for?

Answer 2

It is commonly used to build back ends for Web applications, command-line programs, or any kind of automation that developers wish to perform.

Question 3

What is a REPL?

Answer 3

also termed an interactive toplevel or language shell, is a simple interactive computer programming environment that takes single user inputs, executes them, and returns the result to the user

Question 4

When was Node.js created?

Answer 4

May 27, 2009

Question 5

What back end languages have you heard of?

Answer 5

Python, Java, JavaScript, Ruby, C#, and PHP

Question 6

What is a computer process?

Answer 6

a process is the instance of a computer program that is being executed by one or many threads.

Question 7

Roughly how many computer processes are running on your host operating system (Task Manager or Activity Monitor)?

Answer 7

hundreds

Question 8

Why should a full stack Web developer know that computer processes exist?

Answer 8

Full stack Web development is based on making multiple processes work together to form one application, so having at least a cursory awareness of computer processes is necessary. This will be extremely important when learning about applications made of multiple components, such as clients, servers, and databases.

Question 9

What is the process object in a Node.js program?

Answer 9

The process object is a global that provides information about, and control over, the current Node.js process.

Question 10

How do you access the process object in a Node.js program?

Answer 10

1.console.log(process)
2. node process.js

(just type ‘process’)

Question 11

What is the data type of process.argv in Node.js?

Answer 11

array of strings

Question 12

What is a JavaScript module?

Answer 12

In JavaScript, a “module” is a single .js file (functions and variables that can be exported)

Question 13

What values are passed into a Node.js module’s local scope?

Answer 13

exports, require, module, __filename, __dirname

Question 14

Give two examples of truly global variables in a Node.js program.

Answer 14

global, process, console,

Question 15

What is the purpose of module.exports in a Node.js module?

Answer 15

way to expose things in one module so they’re available in another

Question 16

How do you import functionality into a Node.js module from another Node.js module?

Answer 16

module.exports = add;
->

const add = require(‘./add’);

Question 17

What is the JavaScript Event Loop?

Answer 17

mechanism for asynchronous code / deferring code to be executed later

Question 18

What is different between “blocking” and “non-blocking” with respect to how code is executed?

Answer 18

blocking: won’t let next ones run until it’s done

non-blocking: lets things run asynchronously so that the rest of the system can keep running things (defers work for later)

Question 19

What is a directory?

Answer 19

a folder

Question 20

What is a relative file path?

Answer 20

file within a directory

Question 21

What is an absolute file path?

Answer 21

full length of the file starting from the root

Question 22

What module does Node.js include for manipulating the file system?

Answer 22

fs

Question 23

What method is available in the Node.js fs module for writing data to a file?

Answer 23

fs.writeFile()

Question 24

Are file operations using the fs module synchronous or asynchronous?

Answer 24

asynchronous