Node.JS Flashcards
CodeWithMosh
Node is a framework?
TRUE / FALSE
FALSE
Node is a run time environment for executing JS code
Node works Synchronise or Asynchronise
Asynchronise
Node is good for?
- CPU intensive sites
- I/O disk network access apps
I/O disk network access apps
how to run a JS file in node?
node “name of file”
how to start node in terminal?
node
how to end node in terminal?
control+c twice
in node there is no window object
TRUE / FLASE
TRUE
window.console.log();
Write the above for Node
global.console.log
there is no window object in NODE instead we use the keyword _______
global
var message = ' '; console.log(global.message); //returns in NODE?
undefined
every file in node is considered a _____
module
to load a module we use the ______ keyword
require
require(‘./logger’);
convert to new ES6 syntax
import ‘./logger’;
what we used to indicated current folder
./
period slash
when using node as best practice what should be changed?
var logger = require(‘./logger’);
console. log(logger);
logger. log(“hello”);
var to const
loading module when importing use const so it does not change
variables and functions are scoped to the ______
modules
what is not valid and why?
exports.log = log;
module.exports.log = log;
exports = log;
//this exports is a reference to module.exports function
exports = log;
The path module provides utilities for working with file and directory paths. It can be accessed using:
const path = _________(‘path’);
require
The ________ module provides utilities for working with file and directory paths.
path
The _________ module provides a number of operating system-related utility methods.
OS
The os module provides a number of operating system-related utility methods. It can be accessed using:
const os = ________
const os = require(‘os’);
The ______ module provides an API for interacting with the file system in a manner closely modeled around standard POSIX functions
fs
filesystem
const fs = ________
const fs = require(‘fs’);
when using File System Module there are Asynchronous and Synchronous methods, what should we generally use?
Asynchronous or non blocking
Asynchronous is associated with blocking or non-blocking
non-blocking
Synchronous is associated with blocking or non-blocking
blocking
const fs = require(‘fs’);
const files = fs.readdirSync(____)
./
dot slash
all async methods take a_____ as the last element
function
a name for a signal that something has happened
event
The events module name is always capilatized because its a __________
class
events module are?
- functions - class - variables
class
emit means
make a noise or produce a signal
const EventEmitter = require('events');
const emitter = new EventEmitter();
emitter.emit('messageLogged');
the code above won’t do anything because it’s missing a _____
listener
const EventEmitter = require('events');
const emitter = new EventEmitter();
emitter.addListener is the same as emitter._____
emmiter.on
const EventEmitter = require('events');
const emitter = new EventEmitter();
emitter.________ is the same as emitter.on
addListener
the emitter.on(); takes two parameters
eventName | The name of the event.
listener The callback function
When creating multiple messages in the code below its best to encapsulate them in a ______
emitter.emit(‘messageLogged’);
object
What is an event?
emitter.on(‘messageLogged’, function(){
console.log(‘Listening’);
})
emitter.emit(‘messageLogged’);
emitter.emit(‘messageLogged’);
What is an listener?
emitter.on(‘messageLogged’, function(){
console.log(‘Listening’);
})
emitter.emit(‘messageLogged’);
emitter.on(‘messageLogged’, function(){
console.log(‘Listening’);
})
when a function is inside a class syntax we do not need the ____ keyword
function
To use the HTTP server and client one must require___
(‘http’)
Write a HTTP module, store in a variable
const http = require(‘http’)
NPM stands for?
Node Package Manager
how to get the version of a program?
-v
before adding node packages you need to create ______ file
package.json
to create a .json file we use _____ in the terminal
npm init
to create a .json file with default parameters we add ____ to the termina
npm init –yes
the keyword to install a node package in terminal is ________ and the shortcut is ____
install
i
const _ =
import the underscore npm package
const _ = require (“underscore”);
What are the 3 levels of node Package Mangers
when it views code like: const _ = require ("underscore");- core moduel
- file or folder
- node_modules
const _ = require (“underscore”);
Js knows underscore is not a file or folder as it’s missig the ______
./
dot slash before name
to reinstall NPM dependencies in a new file type __
npm i
in terminal
to list all files and folders from a project we first create a
_____ folder
then create a _______ folder
in the file write___
git init
.gitignore folder
node_modules/
Semantic Versioning
4.5.33
what is 4 called?
what is 5 called?
what is 33 called?
major version
minor version (new features that dont break API)
patch (bug fixes)
an example of Semantic Versioning?
4.5.33
^4.14.5 SemVer is equal to
4.x.5
if you want a NPM package of the same version you remove the _____ or _____
~
to see all NPM packages and versions type in terminal _______
NPM list
the NPM LIST command will give a large tree. What command to just list our packages?
npm list –depth=0
to get the details of an NPM package type
npm view “package name”
to get the details of an NPM package type and ONLY versions
npm view “package name” “versions”
type what in terminal to install mongoose version 2.4.2
npm i mongoose@2.4.2
to check to see what NPM package are outdated tyep??
npm outdated
to update all NPM packages type __?
npm update
the keyword for removing a NPM package is ______ and the shortcut is
uninstall
un
to install a NPM globally like NPM itself use the flag
-g
uninstall an NPM global package
npm un -g “package”
What does REST stand for
REpresentational State Transfer
REST does 4 things called CRUD. What is CRUD?
Create
Read
Update
Delete
what are the 4 main HTTP Methods?
Get
Post
Put
Delete
the NPM that will allow us not to restart the stop the terminal process in a port
nodemon
another name for an environment variable
port
what object do we use to create a port
Process
we want to change the PORT in the terminal, what do we write?
export PORT=
in the code editor how do we reassign a port?
const port = process.env.PORT || 3000;
_______ is a simple minimalistic and lightweight framework for building web servers
Express
Using Express what are the two lines of code for a server?
const express = require('express');
const app = express();the status code of an object not found is
404
a Bad request is number
400
function sayHello(){
console.log("hello!!!!!");
}
// in node the above did not print to the console, why?
did not call the function
sayHello();
function sayHello(na){
console.log(na);
}
sayHello(window);// returns
ReferenceError: window is not defined
var message = ''; console.log(global.message);
Variables and functions in node are scope to their ____
file
modules in JS are ______
objects
REST and HTTP are not same
true/false
true
________ is the protocol that allows for sending documents back and forth on the web
HTTP
the function that is used in node and modules as a IFE is called
Module Wrapper Function
a single thread application is async or sync
sync
What function must go first?
emitter. emit(); //raise an event?
emitter. on(); //listener?
emitter.on();
API stands for?
Application Program Interface
what is middleware
functions have access to the request and response object.
with NPM to install a dev dependency use the flag
-D
middleware functions take 3 parameters
req, res, next
next always last
const logger = (req, res, next) => {
//code
}
// what code here to start logger?
app.use(logger);
