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. 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 2

What can Node.js be used for?wh

Answer 2

Node.js is used for developing applications that make use of the ability to run JavaScript both on the client as well as on the server side.
ex Real time apps , instant messaging / chat apps, streaming app, social media.

Question 3

What is a REPL?

Answer 3

read–eval–print loop (REPL) is an interactive shell / computer programming environment that reads user inputs, executes them, and returns the result to the user;

EX: Chrome Browser Console

Question 4

When was Node.js created?

Answer 4

May 27, 2009 by Ryan Dahl

Question 5

What back end languages have you heard of?

Answer 5

Scripting Langs - Python, Ruby, PHP, JavaScript, Perl, Elixir
(JIT) - just in time compilation
typescript is a good language to learn after bootcamp.

Memory Managed Langs - Java, C#, Kotlin, Golang, Fortan
//These languages are compiled ahead of timt
//garbage collection

Manual Memory Management - C++, C, Swift,
//ahead of time compiled
//low-level

Question 6

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

Answer 6

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

Question 7

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

Answer 7

since it’s a global object it can accessed from anywhere. It can also be accessed using require():

Example: in the exercise we accessed it using console.log().

Question 8

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

Answer 8

Array of strings

Question 9

What is a JavaScript module?

Answer 9

In JavaScript, a “module” is a single .js file.

Question 10

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

Answer 10

exports, require, module, __filename, __dirname

Question 11

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

Answer 11

Process - process object
Console - used to print stdout and stderr
Buffer - used to handle binary data

Question 12

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

Answer 12

Module exports are the instructions that tell Node. js which bits of code (functions, objects, strings, etc.) to export from a given file so that other files are allowed to access the exported code.

Question 13

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

Answer 13

use the require( ) method.
syntax: const varName = require( ' ./filename ' );

Question 14

What is the JavaScript Event Loop?

Answer 14

looks at the task queue then pushes it onto the stack when the call stack is clear the next thing in the queue gets pushed into the call stack.

Question 15

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

Answer 15

blocking code is anything occupying the call stack. Then we have to wait for it to be cleared.

Question 16

What is a directory?

Answer 16

A location for storing files

A.K.A a folder.

Question 17

What is a relative file path?

Answer 17

points to a relative file in the current directory. and contains a portion of the full path.

Question 18

What is an absolute file path?

Answer 18

starts at the root of the file system, starts with a slash.

Question 19

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

Answer 19

the fs module, all methods are asynchronous by default,

Question 20

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

Answer 20

fs.writeFile method - used to asynchronously write the specified data to a file.
syntax - fs.writeFile( file, data, options, callback )

Question 21

Are file operations using the fs module synchronous or asynchronous?

Answer 21

Every method in the fs module has synchronous as well as asynchronous forms. Asynchronous methods take the last parameter as the completion function callback and the first parameter of the callback function as error.

all the methods are asynchronous by default, but they can also work synchronously by appending Sync .

Question 22

What is Webpack?

Answer 22

webpack is a static module bundler for modern JavaScript applications
 it internally builds a dependency graph from one or more entry points and then combines every module your project needs into one or more bundles, 

Webpack is a tool that lets you compile JavaScript modules, also known as module bundler. Given a large number of files, it generates a single file (or a few files) that run your app.

Question 23

How do you add a devDependency to a package?

Answer 23

npm install –save-dev

Question 24

What is an NPM script?

Answer 24

An npm script is a convenient way to bundle commands for your project.
typically commands that you enter in the terminal that runs something in your application.

Question 25

How do you execute Webpack with npm run?

Answer 25

run npm run build in terminal

you need to add the NPM script “build”: “webpack”