Node/Express/Fetch

Question 1

What is Node.js?

Answer 1

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

Question 2

What can Node.js be used for?

Answer 2

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

read-eval-print loop. 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; a program written in a REPL environment is executed piecewise. browser console is REPL.

Question 4

When was Node.js created?

Answer 4

May 27, 2009

Question 5

What back end languages have you heard of?

Answer 5

Scripting Languages: These are interpreted on-the-fly
jit - just in time compilation
JavaScript (jit), Ruby (jit), Elixir, PHP, Python, Perl, Erlang
what to learn after BootCamp: TYPESCRIPT, any other languages job rec.

Memory Managed Languages: These languages are compiled ahead of time
Java/Kotlin, C#, Golang, Haskell, Julia, F#, Fortan

Manual Memory Management: ahead of time compiled (low-level language)
C++, C, Swift, Rust, D, Zig

SQL - for Database

Question 6

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

Answer 6

The process object in Node. js is a global object that can be accessed inside any module without requiring it

Question 7

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

Answer 7

execute the node command with the js file that has the console.log(process); in it… or maybe process

Question 8

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

Answer 8

an array of strings.

Question 9

What is a JavaScript module?

Answer 9

A single JS file.
A file containing related code. technique that emphasizes separating the functionality of a program into independent, interchangeable modules, such that each contains everything necessary to execute only one aspect of the desired functionality.

Question 10

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

Answer 10

exports (object), require (function), module (object), __filename (string), __dirname (string)

Question 11

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

Answer 11

console, process, global

Question 12

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

Answer 12

The main purpose of module. exports is to achieve modular programming. Modular programming refers to separating the functionality of a program into independent, interchangeable modules, such that each contains everything necessary to execute only one aspect of the desired functionality.

Question 13

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

Answer 13

call the require function and get the relative path as argument and assign it to a variable.

Question 14

What is the JavaScript Event Loop?

Answer 14

responsible for collecting the event and running when the stack is empty. event loop looks at the task queue and pushes it back to stack when stack is empty (call stack is cleared).

look at stack and look at the task queue, if stack is empty, it takes the first thing on the queue and pushes it on to the stack ONCE everything on the stack is cleared. which effectively runs it. stacks up on task queue(s) / call back queue and pushes it back to stack to be run.

Question 15

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

Answer 15

blocking: synchronous. need to wait for a process to finish before the next line of code runs. it blocks the next code to run until the current is finished. blocking is occupying the call stack so it can’t do anything until it’s cleared. anything occupying the call stack is blocking.

non-blocking: asynchronous callbacks. is able to run other code/thing while it’s running one code/thing.

Question 16

What is a directory?

Answer 16

it is a file directory

Question 17

What is a relative file path?

Answer 17

path to somewhere from where the current file

Question 18

What is an absolute file path?

Answer 18

starts with a root of the file system “/”

Question 19

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

Answer 19

fs module.

Question 20

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

Answer 20

writeFile

Question 21

Are file operations using the fs module synchronous or asynchronous?

Answer 21

both synchronous and asynchronous

Question 22

How do you add express to your package dependencies?

Answer 22

make sure to create a package.json first with “npm init” command
after that use “npm install express”

Question 23

What Express application method starts the server and binds it to a network PORT?

Answer 23

listen() method.

var express = require(‘express’)
var app = express()
app.listen(3000)

Question 24

How do you mount a middleware with an Express application?

Answer 24

use() method

Question 25

Which objects does an Express application pass to your middleware to manage the request/response lifecycle of the server?

Answer 25

request object and response object
req is a data model of HTTP request message (FROMthe client)
res is a data model of the HTTP response message (TO the client)

Question 26

What is the appropriate Content-Type header for HTTP messages that contain JSON in their bodies?

Answer 26

application/json.

Question 27

What does the express.json() middleware do and when would you need it?

Question 28

What does the express.json() middleware do and when would you need it?

Answer 28

It parses incoming requests with JSON payloads. Returns middleware that only parses JSON and only looks at requests where the content-type header matches the type option.

Question 29

What does express.static() return?

Answer 29

method of express object that returns a function.
express.static(publicPath) returns a function

is a built-in middleware function in Express, syntax
express.static( root, [options] )

Question 30

What is the local __dirname variable in a Node.js module?

Answer 30

absolute path to the current module’s directory

Question 31

What does the join() method of Node’s path module do?

Answer 31

combines the paths together.

joins all given path segments together using the platform-specific separator as a delimiter, then normalizes the resulting path

Question 32

What does fetch() return?

Answer 32

a promise. promised to get a response (res). a server responded, here is the response message

Question 33

What is the default request method used by fetch()?

Answer 33

‘GET’ request.

Question 34

How do you specify the request method (GET, POST, etc.) when calling fetch?

Answer 34

const request = {
method: ‘POST’

};

as [option], a second argument.

Question 35

When does React call a component’s componentDidMount method?

Answer 35

after the successful render() . it has finished loading the render() method,

Question 36

Name three React.Component lifecycle methods.

Answer 36

constructor()
render()
componentDidMount()
componentDidUpdate()
componentWillUnmount()

Question 37

How do you pass data to a child component?

Answer 37

through props

Userlist users(<- this is the prop that will be passed)