node.txt

server-side JavaScript runtime environment built on Chrome's V8 JavaScript engine
It allows developers to run JavaScript code outside the web browser, typically on the server side

Pros
------
Non-Blocking I/O
---------
Node.js is based on an event-driven, non-blocking I/O model, which allows it to handle multiple concurrent connections efficiently.
This makes it well-suited for building real-time applications, such as chat applications, online gaming platforms, and streaming services

Performance
-----------
compiles JavaScript code into native machine code for execution. This results in high-performance applications with fast response times

NPM Ecosystem and Community and Support

Cons
-------
Single-Threaded
--------------
Node.js is single-threaded, meaning it uses a single event loop to handle all incoming requests

Callback Hell
------------
multiple nested callback functions are used to handle asynchronous operations

asyncFunction1(function(result1) {
    asyncFunction2(result1, function(result2) {
        asyncFunction3(result2, function(result3) {
            asyncFunction4(result3, function(result4) {
                // Do something with result4
            });
        });
    });
});

overcome the single-threaded
-----------
Use Worker Threads
------------
allows you to create and run multiple threads of execution alongside the main event loop

callback
-----------
A callback function in JavaScript is a function that is passed as an argument to 
another function and is executed after some asynchronous operation.

advantages of using promises instead of callbacks
-------------
built-in error handling and Improved readability

uses of node js
---------
Real-time chats, Internet of Things, Streaming applications, Microservices architecture

modules
----------
modules are reusable units of code. They allow you to organize your code into smaller, manageable pieces, making it easier to 
maintain, reuse, and share across different parts of your application.

core modules => require('path')
File modules => require('./app.js')

Why is Node.js preferred for backend?
--------------
Node.js is very fast
Node Package Manager
real-time web applications, as Node.js never waits for an API to return data
Better synchronization of code between server and client due to same code base

Event Loop 
------------
Event loops handle asynchronous callbacks in Node.js. It is the foundation of the non-blocking input/output in Node.js

EventEmitter
---------------
Node.js uses events module to create and handle custom events
The EventEmitter class can be used to create and handle custom events module

types of API functions in Node.js
------------
Asynchronous non-blocking functions and Synchronous blocking functions

package.json file?
-------------
The package.json file is the heart of a Node.js system. This file holds the metadata for a particular project.

Express JS
--------
is a minimalist and flexible web application framework for Node.js
Is creating server-side logic and handling HTTP requests 

Routing
--------
It allows you to define routes to handle different HTTP requests
GET,POST,PUT,DELETE,PATCH

Error Handling and RESTful API Development

streams in Node.js?
------------
Streams are objects that enable you to read data or write data continuously.

Types => Readable (used for), Writable, Duplex (both read and write), Transform

REPL ( Read Eval Print Loop) in Node.js?
-----------
It’s similar to a Windows console or Unix/Linux shell in which a command is entered
Read - reads users input 
Eval - evaluates the data structure
Print - print the result 
Loop - Loops above the comments

buffer class in Node.js
-------------
Buffer class stores raw data similar to an array of integers but corresponds to a raw memory allocation outside the V8 hea

piping in Node.js?
-------------
Piping is a mechanism used to connect the output of one stream to another stream

middleware
------------
Middleware is a function that receives the request and response objects
Used for, Update or modify the request and the response objects and Finish the request-response cycle

types of HTTP requests?
GET,POST,PUT,DELETE,PATCH

Node.js timing features
---------------
setTimeout, clearTimeout
setInterval, clearInterval
setImmediate, clearImmediate

Node.js better than other frameworks?
----------------
Node.js is a server-side JavaScript runtime environment built on top of the V8 JavaScript engine, the same engine that powers Google Chrome
Node.js very fast and efficient, as well as highly scalable. 

fork in node JS?
-----------
The Fork method in Node.js creates a new child process that runs a separate Node.js instance

JavaScript Vs Node.js
-------------
Feature | JavaScript | Node Js
Definition | JavaScript is a programming language | Node.js is a runtime environment
Execution | Runs in web browsers | Runs on servers
Platform | web | server
Event Loop | Not applicable (applicable by web browser) | applicable 

asynchronous vs synchronous 
------------------
Feature | asynchronous | synchronous
Execution | without waiting for the task to complete |  waiting for each task to complete before moving on to the next one.
Task Handling | Handles tasks that involve I/O operations | Handles tasks that are CPU-bound
Control Flow | Uses callbacks, Promises, or async/await | Follows a linear execution flow
Error Handling | Requires careful error handling | Errors are easier to handle

primary reason for using the event-based model in Node.js?
-----------------
The main reason to use the event-based model in Node.js is performance.
Node.js can handle a large number of connections without using a lot of resources.

Node run on Windows?
---------------
Yes, Node.js runs on Windows. Node.js is a cross-platform runtime environment

access DOM in Node?
--------------
No, you cannot access the DOM in Node.js. DOM is a browser-specific API,
Since Node.js does not run in a browser

stub in Node.js
--------------
stub is a function that serves as a placeholder for a more complex function. Stubs are typically used in unit testing 

LTS releases of Node.js?
-------------
LTS stands for Long-term support. LTS releases of Node.js are versions that are supported for an extended period, usually for 30 months from the time of release

ESLint ?
----------
ESLint is a popular open-source tool that is used to analyze and flag errors

Node.js handle the child threads?
---------------
Node.js handles child threads by creating separate instances of the Node.js runtime environment that can be used to execute code in parallel with the main process.

microservices
----------
microservices refer to an architectural approach for building applications as a collection of small, independent services
Each service focuses on a specific services

MVC (Model-View-Controller)
----------------
is a popular architectural pattern used in Node.js development for structuring web applications

Model => This component represents the data and business logic of your application.
View => This component deals with the user interface (UI) representation of your application
Controller => This component acts as the intermediary between the model and the view.

Code Reusability and Testability

functions vs middleware
---------------
features | functions | middleware
Purpose | Reusable block of code performing a specific task | Intercepts requests and responses in the application flow
Arguments | any arguments | req,res,next
Return Value | any value | modified req,res
Scope | called from anywhere | Executed in a chain during request processing
usages | calculations, logic execution | Authentication, authorization, logging, error handling
Reusability | Highly reusable across different parts | Designed for specific middleware tasks

body parser
----------
is a middleware that simplifies handling incoming HTTP request bodies

Simplified Data Access, Format Handling, improved Developer Experience

Cron
--------
Cron, in the context of Node.js, refers to scheduling tasks to run at specific intervals.
It's not a built-in functionality of Node.js

every minutes => * * * * * (minutes hour day month week)
every 2 minutes => */2 * * * *

CORS (Cross-Origin Resource Sharing)
----------------
is a mechanism that restricts web browsers from making requests to a different domain 

node red?
----------
Node red is a visual programming tool for Node.js that is used to wire 
hardware devices and online services as part of IoT applications.

Redis
------
Redis is an open-source, in-memory data structure store that can be used as a database, cache, and message broker.
it is commonly referred to as a data structure server

Session Storage, Queueing, Caching, Pub/Sub Messaging

Query Parameters (req.query)
----------
Query parameters are key-value pairs appended to the end of a URL after a question mark 

Route Parameters (req.params)
-----------
Route parameters are dynamic parts of the URL path specified using placeholders in the route definition

Request Body (req.body)
--------------
The request body contains data sent by the client as part of an HTTP request
data form are JSON and form data