NotesWithRoadMap.txt

FULL STACK COURSE 2023
REACT MasterClass Course Material - HERE
React MasterClass 2023 Video

Assignment Solutions Video

MongoDB ip address 0.0.0.0/0 by default.

NODE MasterClass Course Material - HERE
NODE 2023 Video
Redux MasterClass Course Material - HERE
REDUX 2023 Video
React JS MasterClass
Hi, This is course page of CoderDost Youtube Channel React JS 2023 Course Video Link ,

How to use this code :
You can download code in 2 ways :
Git Commands

use git clone <repository_url>

checkout branch according to Chapter number git checkout react-1

run npm install inside the root directory before running the code

If you are not comfortable with git, directly download the branch as Zip.

Choose branch related to the Chapter e.g. react-1

run npm install inside the root directory before running the code

React JS Series
Chapter 1 - Introduction to React & Setup
Assignment 1 : If we delete node_modules. How to run our app again successfully ?

Assignment 2 : How to remove double console.logs from React ? [ it is not needed in real life to remove them, its just an assignment problem ]. [ Hint: Some special Component at top level is of App is causing it ]. We explore more about - why this is needed in later videos.

Special Assignments ==============
Assignment 3 : Create a Page with multiple React Apps. Both React Apps should be independent of each other.

Assignment 4 : Try to build a react app using other toolchains like Vite

Related Videos :
De-structuring Assignment : Long Video | Object De-structure Short Video | Array De-structure Short Video
Import/Export : Long Video | Short Video
Chapter 2 - Components - JSX and Props
Assignment 1 : Create a simple React app for RESUME Builder. It will be static website. You have to make components like Resume as top level and under it - Skills, Education, Experience etc as components. All resume data will be under 1 big JavaScript object like which you can us in components via props. You can fix the number of items in Skills, Education, Experience or any section. Example you can say that only 3 experience items is allowed.

 resume = {
    experience : [ { year:2012, company:'xyz', role:'something' }],
    education:[ ],
    skills : [ 'react js', 'node js']
    .....
    ...
    }
You can choose any simple HTML layout and convert it to React Components

Example Link : Resume HTML

Special Assignments ==============
Assignment 2 : Create a Parent Component called Border which can provide some CSS border to any component nested into it. [Hint : You will need to use children props here

 < Border> 
       < Component > 
 < Border />
Related Videos :
De-structuring Assignment : Long Video | Object De-structure Short Video | Array De-structure Short Video
Import/Export : Long Video | Short Video
Spread Operator : Long Video | Short Video
Chapter 3 - Conditional Rendering & Lists
Assignment 1 : Make a simple component which can conditionally render a list with number or alphabets or bullets in HTML for number. e..g. use a prop like layout for this. Also use a prop items for array of items in list.
< List layout="numbered" items={items}/> 
< List layout="alpha"  items={items}/> 
< List layout="bullet"   items={items}/>
Assignment 2 : This is continuation of previous assignment RESUME Builder

In this part you have to make some conditional rendering. Suppose if any section doesn't exist you have to remove that section from Resume. Example if skills is empty array than don't display skills section in Resume.
You have to use map in most places where there are arrays. Like Skills, Education, Experience if there are 3 entries, use map to display 3 experience items. You don't need fix number of items. Any array can have 1 to 10(or some Limit) any number of items. You can put some Limit, so that your layout is not affected.
Conditionally put some styling to Resume. Like light theme or dark theme or any other way you can switch the CSS layouts.
 resume = {
    experience : [ { year:2012, company:'xyz', role:'something' }],
    education:[ ],
    skills : [ 'react js', 'node js']
    .....
    ...
    }
You can choose any simple HTML layout and convert it to React Components

Example Link : Resume HTML

Related Videos :
Ternary Operator : Video
Logical AND (&&) : Video
Higher Order functions (map, filter, reduce) : Video
Import/Export : Long Video | Short Video
Chapter 4 - Events && Event Bubbling
Assignment 1 : Make a simple page with 1 Image, 1button, 1 form Input text box and try to apply these events .

Image : onMouseOver : when you hover on image. Image should increase in size. Think of any way where you can do it. Also, try that when you "move out" the mouse, it should be back to normal size.
Button : onDoubleClick: when you doubleClick a button. show some alert box. Also make a console.log for single click event. Is console.log printed twice on double click ? check this ?
Input Textbox : onFocus, onBlur are 2 events which occur when you enter or exit an input text box by click of mouse etc. Use it to display some console.log, which print "focused on the textbox", "out of textbox".
onCopy, onCut, onPaste are 3 events which you can use on any text value etc. try to use it on a paragraph and just alert the user that something is copied, cut or pasted.
Assignment 2 : Make a form using < Form> tag and put an textbox and button inside this form. try to click the button after entering into textbox. Does form reloads ? Can you try to stop is using e.preventDefault. Try it.

Assignment 3 : use an Input Textbox : after you enter some text. try to press ENTER button and show the an alert or console.log. You can capture the onKeyPress event, button how you will you make it work only for "Enter" ? It should not work on pressing of other keys. [Hint: Explore the synthetic event object ]

Assignment 4 : This is continuation of previous assignment RESUME Builder.

Add a print button to print the current resume. You can use a DOM method window.print to print the PDF.
Assignment 5 : Can you try the challenge of passing the function in one Prop like onPlay and the message inside that function to be accessed from other prop message [ As shown in Chapter Video ]

Special Assignments ==============
Assignment 6 : Using event bubbling concept print the name of Parents to Child of any clicked element. It should be order in "GrandParent >Parent > Child" this kind of order. Where "Child" represents the current clicked element.

Assignment 7 : Make a custom event called onClose. this event should close the current browser tab. you can apply it to a button on click or anywhere.

Related Videos :
HTML DOM Elements and manipulation Video
HTML DOM Events and manipulation : Video
Chapter 5 - State, useState Hooks
Assignment 1 : Make a digital CLOCK Component using useEffect Hook. We need to only update the time Upto seconds in it. HH:MM:SS format can be used. Can you make it send a Console.log at end of every minute ?

Assignment 2 : Implement a simple TIMER that displays the elapsed time since the start button was pressed, and it can be stopped and reset. Like a stopwatch.

Chapter 6 - Form , Synthetic Event Object & Lifting State up
Assignment 1 : Create a Dropdown (< Select >) menu which is formed by a nations array. You can push to this array new items using a 2 input textbox (for country name and code) and button. On selection of the any option from dropdown, its value should be displayed on console.log
const  nations  = [
{ name:  'India', value:  'IN' },
{ name:  'Pak', value:  'PK' },
{ name:  'Bangladesh', value:  'BG' },
] 
Assignment 2 : FILTERED LIST : Make a List of something using an Array (a list can of cricket player /countries/ movie name etc). Now make this list it searchable, you have to put a input textbox at top of list. When you type in textbox it should only show you items matching from text typed. For example - If you type only "in" it should show things like "India" / "China" as both have in in it.

Assignment 2.1 : FILTERED LIST : Make above List as separate components for List, Input form and pass the states from each other using concepts learnt till now.

Assignment 3 :

This is continuation of previous assignment RESUME Builder. Now you have to make a separate component ResumeEditor which has a FORM. This form will have many input boxes. Each one related to one section. For example you can have one input box or experience section. Another input box for skill section and like this. Every input box should have an Add button in front of it. Once you press this add button that information is stored in the state , which you can update at top of the App level. Now this state should update the Resume Component and its child you have built.

first component will be your RESUME document which is only for reading purpose.

second component will be this FORM

you have to manage the state in between

only Add functionality is required in this assignment

you can change input boxes according to your need depending on your format of Resume. You can have multiple textboxes also for same section. Like for date + experience item etc.

Assignment 4 : Try this challenge : https://beta.reactjs.org/learn/state-a-components-memory#challenges

Related Videos :
HTML Forms-1 Video
HTML Forms-2 : Video
MINI PROJECT
Project 1 - TODO App
Todo app can be used to maintain a list of your pending daily items. A Simple todo list must have these features

You can add any new item to TODO list
You can click on any item to mark it as done, if you have done that by mistake - you can click again to undo.
You can delete any item (completed or pending)
You get a total of completed items and overall items on the list.
You can move list items "Up" or "Down" using buttons.
Output

Additional Features
KEYBOARD BASED Features :

use ENTER key on keyboard to add a new item.
when you click on an item, it should be selected (you can change style to show it is selected)
If you press the DELETE key on the keyboard after selecting the list item it should delete that list item. If you have not selected any item the last item should be deleted.
You can select list item and press UP arrow key to Move It Up. And you can press the DOWN key to move it down.
Other Features :

Pin element to Top of List : On double click make element reach top of list. You can show a different color also to show that element is pinned.
Show the date & time at which list item was added.
Order by : Todo Item names, Date added, Completed.
Due date feature : Add a due date of task of any todo item. You will need to add another input box for this at top. Whenever you are in 24 hour limit of due date - Task outline will be shown in ORANGE color. e.g if a task is due on 23 May - from 22nd May it should show in ORANGE outline color. If a due date is passed task should show RED Outline.
Use some component like https://github.com/react-component/progress to show a progress bar at top of list. This progress bar will show how much of total percent of tasks are completed.
Delete item via swipe gesture - like swipe to right on mobile phone. [Hint: You have to find an event type for this ]
Advanced Features :

Use localStorage in browser using libraries like https://github.com/localForage/localForage to make your todo list permanent in browser. This will have your list stored in browser database and will not delete it on refresh or closing of browser. LocalStorage Video LocalForage Video
ANIMATION BASED Features [optional] :

Enter Animation : Animate list item on adding.
Exit Animation : Animate list item at removal.
Chapter 7 - More State & useEffect hooks
Assignment 1 : The method shown in this video was just to introduce useEffect hook. However that was not the correct use of useEffect hook. Can you change the code to remove useEffect and still have the editVideo functionality. [ Hint : use the concept that Component is rendered every time prop changes ]

Assignment 2 : This is continuation of previous assignment RESUME Builder.

Add functionality to delete the items from resume.
Add functionality to update the items from resume.
you have to manage the state in between
you can change input boxes according to your need depending on your format of Resume. You can have multiple textboxes also for same section. Like for date + experience item etc.
Check the output can be printed perfectly in PDF.
Chapter 8 - useReducer
Assignment 1 : Try this challenge : https://beta.reactjs.org/learn/extracting-state-logic-into-a-reducer#challenges

Assignment 2 : Convert your RESUME BUILDER Application from useState to useReducer by converting states logic to a common reducer. Your reducer can have as many switch cases as you want. You can also divide them based on sections. ADD_SKILL, ADD_EXPERIENCE etc. to make logic even simpler for developer.

Related Videos :
REDUX - Understand it in Simple way Video
Chapter 9 - Context API & useContext
Assignment 1 : Try this challenge : https://beta.reactjs.org/learn/passing-data-deeply-with-context#challenges

Assignment 2 : Add a Context to your RESUME BUILDER to change font-size, font-color and some other font-properties. Also add a form to changed these property at top of App.

Assignment 3 : Add a Context to your RESUME BUILDER to change Dark Mode and Light Mode. You can also use a React Switch kind of library to make it more user friendly to switch.

Chapter 10 - Context API with useReducer [Redux architecture]
Special Assignments
Assignment 1 : Make a useCounter Hook: To keep track of a number that can be incremented or decremented.
const [count, increment, decrement] = useCounter(0);
Chapter 11 - useRef
Assignment 1 : Try this challenge:
https://beta.reactjs.org/learn/referencing-values-with-refs#challenges

Assignment 2 : Try this challenge:
https://beta.reactjs.org/learn/manipulating-the-dom-with-refs#challenges

Assignment 3 : Make a useWindowSize Hook: which returns size of current browser window.

const [width, height] = useWindowSize();
Related Videos :
Complete DOM Course playlist Video
Chapter 12 - useEffect and API calling
Assignment 1 : Try this challenge :
https://beta.reactjs.org/learn/synchronizing-with-effects#challenges

Assignment 2 : Try this challenge :
https://beta.reactjs.org/learn/removing-effect-dependencies#challenges

Assignment 3 : Try this challenge :
https://beta.reactjs.org/learn/reusing-logic-with-custom-hooks#challenges

Assignment 4 Use JSON Placeholder API (link given below).
You have to create a button which can get some posts and show them in a List.

You have to a show comments button on each list item. On click of show comments, Post's comments should be fetched below that list item. [ Comments are available for each post in API]

When you click on a particular list item's show comments, it should expand and show comments, otherwise it should collapse and hide the comments.

Try to optimize by :

Only getting comments of required Post items (not all at a time)
Storing somehow the old comments of closed list items. So you will not fetch them again, when your show comments again.
enter image description here

Related Links :
Mockaroo fake data APIs Link
JSON placeholder API Link
Chapter 13 - Memoization - useMemo, useCallback, memo
Assignment 1 : Implement a component that displays a list of items. The component should memoize the list of items to prevent unnecessary re-rendering.

Assignment 2: How to use memoization in the JSON Placeholder API assignment in previous problem. Can you try to optimize it using useMemo/useCallback ?

Assignment 3: useMemo and useCallback are same hook. useCallback is just a convenient hook way to write useMemo for functions. Prove this using useMemo in place of useCallback in any previous problem. [ Hint : you will have to change the useMemo callback and return the function definition ]

Chapter 14 - Advanced React - Part 1
Assignment 1 : Try to apply useDeferredValue and useTransistion hooks on API based components. Either make a new one or use any existing code you have from other assignments. You can use Chrome Network throttling from Devtools > Performance Tabs and use Slow 3G option to see the effects
Chapter 15 - Advanced React - Part 2
Assignment 1 : Try to use window.print functionality as show in code without flushSync and see if really make a difference. Also, try the same on alert functionality, can it also work ?
--- END OF REACT COURSE ------

Node JS MasterClass
Hi, This is course page of CoderDost Youtube Channel NODE JS 2023 Course Video Link

How to use this code :
You can download code in 2 ways :

Git Commands

use git clone <repository_url>

checkout branch according to Chapter number git checkout node-1

run npm install inside the root directory before running the code

If you are not comfortable with git, directly download the branch as Zip.

Choose branch related to the Chapter e.g. node-1

run npm install inside the root directory before running the code

NOTE : Code for React JS app is available in final code node-12 branch in folder react-app. It can be used in previous chapters also like chapter-8 etc (however it's the final code, so step-wise code is not available for React, However one can follow the tutorial and make it , sorry for inconvenience)

Chapter 1 - Introduction to Node, NPM, Package.JSON
[[ Chapter Notes ]]
Node JS installation from official site nodejs.org - use only LTS versions
Use terminal / command prompt to check installation : node -v npm -v 
VS Code installation directly from code.visualstudio.com site
Use VS code terminal to run commands
Node REPL interface can be used directly by typing node in terminal / command prompt . Use Ctrl+D to exit interface. Use CTRL+C to exit terminal
Running any JavaScript file from node using node filename.js
Modules are basic containers in Node/JavaScript system. 1 file can be one module in Javascript.
Two type of Module Systems in node JS are - CommonJS module and ES Modules.
- CommonJS Module

//lib.js
exports.sum = function(){}

//index.js
const module = require('./lib.js')
module.sum();
- ES Module

//lib.js
export {sum}

//index.js
import {sum} from './lib.js'
	
FileSystem Module(fs) is one of core modules of Node JS. fs can be used to read/write any file. There are many more core modules in NodeJS which you can check in NodeJS API docs.

Reading files can be Synchronous or Asynchronous. Async is most preferred method in NodeJS. As there is NO blocking of I/O in NodeJS

Node project can be initialized with npm init command which also creates package.json file

package.json is a configuration file for node projects which has scripts, dependencies, devDependencies etc

npm install <package-name> is used to install any online modules available for node on NPM repository online.

nodemon is a package for running node server and track live changes to re-start again.

scripts inside package.json can be used like npm run <script-name> e.g npm run dev. Only for npm start you can avoid run.

use npm install -g <package.json> to install packages globally on your system. Not just in the project but useful all over your system.

Node versions are formatted like 4.1.9 where these are major.minor.patch versions.

you can install all dependencies again using npm install again

package-lock.json has exact versions installed and link of dependencies of each package.

use npm update to update packages safely. npm outdated shows outdated and latets versions of packages installed in your package.json

use npm uninstall <package-name> to uninstall packages from package.json

node_modules should not be shared - you can make .gitignoreto ignore them to be uploaded.

[[ Assignments ]]
Assignment 1 : If we delete node_modules. How to run our application again successfully ?
Assignment 2 : How to use command line arguments in Node JS. Like node index.js 3 2 - how can I get 3 and 2 to be used in my programs. [ Hint : search for command line arguments in node ]
Assignment 3 : Explore the os module in Node Js from their documentation. What all info you can access from it about your operating system ?
Assignment 4 : Explore about Asynchronous nature of JS as a single threaded language and how it is achieved using Event Loop. Video are given below in related videos sections.
Assignment 5 [Challenge] : Can you run a system command from Node JS javascript file e.g. ls dir commands ? and can you store its output in a text file ?
Related Links/Videos
Callbacks
Promises
Async Await
Import/ Export example
Event Loop in Node JS
Chapter 2 - Server Concepts with Node - http module
[[ Chapter Notes ]]
HTTP requests
Request object comprises of many properties, but important ones are :

Type of Request : GET, POST, PUT, DELETE etc.
Headers : Meta data sent by your browser like browser name, cookies, authentication information etc.
Query Parameters (url?name=john) : This is used in GET requests to send data to server
Route Params (url/john)
Body data : This is used in POST and other requests to send data to server
HTTP responses
Response object comprises of many properties, but important ones are :

Headers : Meta data sent by your server back to client like server name, content size, last updated time etc.
Response status code (200, 404, 403, 502)
Response body : Actual data to be sent to client : HTML, JS, JSON, CSS, Image etc.
More info
HTTP requests and responses can be tracked from Dev Tools > Network Tab

In Node, we can use core http module to create a Server which listens to requests, modify data in-between and provides responses. Server needs a PORT to be bound to - use only port number > 1024.

Server can simply be said as a function which receives a request and returns a response. [ This is just for understanding]

There are many Headers which exists on request and responses - shared a link below with list of existing headers.

We can use Server to do 3 things:

Static file Hosting : Sending normal files without formatting or modifying.
Server Side Rendering : Mixing data with templates and rendering dynamic views (dynamic web pages)
Web APIs : Sending data via some APIs/ endpoints.
Every Request has one and only one response. If there is more than 1 response which you want to send - you will encounter a error - "Headers already sent"

POSTMAN is a software for doing complex API requests.

[[ Assignments ]]
Assignment 1 : Capture the request which goes when you like a post on facebook (using Chrome network). What are the headers ? What is the payload ?
Assignment 2 : In the chapter we developed a server with only URL switch, but you have to make that more efficient by making it check both METHOD (GET,POST) + URL path
So output of a request with GET /demo will be different from POST /demo [ Use POSTMAN for requests]
Assignment 3 [Challenge] : Try and run 2 different server using the same code you have index.js. You will need to use 2 different ports. But can you do it using the same file and changing PORTS dynamically somehow ?
Assignment 4 [Challenge] : You can also send some data to server using /demo?product=123. where product=123 is called query parameters. Can you capture that data and make the product page work according to the ID (123) . [ This we will do in next chapters using express, but you can give it a try ]
Related Links/Videos
Web Server Concepts in 1 Video
List of HTTP headers
List of HTTP methods
dummy JSON site
Chapter 3 - Express JS
[[ Chapter Notes ]]
ExpressJS is de-facto Node framework - and used in most Node applications which are used as web server.

You can install express npm install express

Express has few level of methods :

Application methods : e.g. app.use()
Request methods
Response methods
Middleware methods
Router methods
Response methods (res is our response objects)

res.send() - for sending HTML
res.sendFile() - for sending File
res.json - for sending JSON
res.sendStatus(404) - for sending HTTP status only
HTTP Request Types we generally use :

GET
POST
PUT
DELETE
PATCH
API / Endpoints / Routes are used inter-changeably but they are related to server paths.

Middle-ware : Modifies the request before it reaches the next middleware or endpoints.

Sequence of middleware is very important, as first middleware is first traversed by request.

Middle-wares can be used for many use cases, like loggers, authentication, parsing data etc.

Middle-ware can be :

Application level : server.use(middleware)
Router level : server.get('/', middleware, (req,res)=>{})
Built-in middleware : express.json() [ for parsing body data], express.static()[for static hosting]
External Middle-wares - like morgan
Request properties (req is our request object)

req.ip - IP address of client
req.method - HTTP method of request
req.hostname - like google.com / localhost
req.query - for capturing query parameters from URL e.g. localhost:8080 ? query=value
req.body -for capturing request body data (but its needs a middleware for body data decoding)
req.params - for capturing URL parameters for route path like /products/:id
Static Hosting : we can make 1 or more folders as static hosted using express.static middleware. server.use(express.static(< directory >)) Static hosting is like sharing a folder/directory and making its file readable as it is. Note : index.html is default file which would be read in a static hosted folder, if you don't mention any file name.

3 major ways of sending data from client to server via request are :

1. Send data via URL in Query String

This is easiest method to send data and mostly used in GET request.

When you have URL with ?name=Youstart&subject=express at end, it translates in a query string. In query string each key,value pair is separated by = and between 2 such pairs we put &.

To read such data in express you can use req.query :

server.get("/demo",function(req,res){
    console.log(req.query) // prints all data in request object
    res.send(req.query);  // send back same data in response object
})
Assignment 1 :
Make above server with API endpoint /demo as shown above :

Try to call this API in your browser http://localhost:8080/demo?name=Youstart - this will return a response of req.query JSON object

Create 3 query parameters name, age, subject with some values. Check the final output of req.query - can you find all data on server side. Can you send it back to client via res object.

2. Send data via Request Params

In this method you can have a URL with url path like /Youstart/express at end it translates in a param string. In param part string each value is separated by /. As you can see that URL only contains value not the key part of data. key part is decided by the endpoint definition at express server

server.get("/demo/:name/:subject",function(req,res){ console.log(req.params) // prints all data in request object res.send(req.query); // send back same data in response object })

So sequence of values matter in this case. As values sent from client are matched with name and subject params of URL later.

Assignment 2 :
Make above server with API endpoint /demo as shown above :

Try to call this API in your browser http://localhost:8080/demo/Youstart/Express - this will return a response of req.params JSON object

Create 3 URL params name, age, subject . Call the URL and check the final output of req.params - can you find all data on server side. Can you send it back to client via res object.

3. Send data via Request Body

Final method of sending data is via body part of request. We can send data directly to body using URL. We have to either use one of these methods

Use a HTML Form and make method value as POST. This will make all name=value pair to go via body of request.

Use special browsers like POSTMAN to change the body directly. (We will see this example in next classes)

server.post("/demo",function(req,res){
    console.log(req.body) // prints all data in request object
    res.send(req.body);  // send back same data in response object
})
Related Links/Videos
Middleware Explanation video
List of useful 3rd party middleware for Express
List of HTTP response status
Chapter 4 - REST API using Express JS
[[ Reading Material ]]
HTTP Methods
The HTTP method is the type of request you send to the server. You can choose from these five types below:

GET : This request is used to get a resource from a server. If you perform a GET request, the server looks for the data you requested and sends it back to you. In other words, a GET request performs a READ operation. This is the default request method.

POST This request is used to create a new resource on a server. If you perform a POST request, the server creates a new entry in the database and tells you whether the creation is successful. In other words, a POST request performs an CREATE operation.

PUT and PATCH: These two requests are used to update a resource on a server. If you perform a PUT or PATCH request, the server updates an entry in the database and tells you whether the update is successful. In other words, a PUT or PATCH request performs an UPDATE operation.

DELETE : This request is used to delete a resource from a server. If you perform a DELETE request, the server deletes an entry in the database and tells you whether the deletion is successful. In other words, a DELETE request performs a DELETE operation.

REST API are a combination of METHODS( GET, POST etc) , PATH (based on resource name)

Suppose you have a resource named task, Here is the example of 5 REST APIs commonly available for task.

READ APIs :
GET \tasks : to read all

GET \task\:id : to read a particular task which can be identified by unique id

CREATE APIs :
POST \tasks : to create a new task object (data will go inside request body)
UPDATE APIs :
PUT \task\:id : to update a particular task which can be identified by unique id. Data to be updated will be sent in the request body. Document data will be generally totally replaced.
PATCH \task\:id : to update a particular task which can be identified by unique id. Data to be updated will be sent in the request body. Only few fields will be replace which are sent in request body
DELETE APIs :
DELETE \task\:id : to delete a particular task which can be identified by unique id.
[[ Chapter Notes ]]
REST API is a standard for making APIs.
We have to consider a resource which we want to access - like Product
We access Product using combination of HTTP method and URL style
REST API ( CRUD - Create , Read , Update, Delete) :

CREATE

POST /products - create a new resource (product)
READ

GET /products - read many resources (products)
GET /products/:id - read one specific resource (product)
UPDATE

PUT /products/:id - update by replacing all content of specific resource (product).
PATCH /products/:id - update by only setting content from body of request and not replacing other parts of specific resource (product).
DELETE

DELETE /products/:id - delete a specific resource (product).
[[ Assignments ]]
Assignment 1 : Make an API similar to explained above for Quotes take dummy data from same site (dummy json quotes)
Related Links/Videos
Middleware Explanation video
Chapter 5 - Backend Directory Structure / MVC / Router
[[ Chapter Notes ]]
MVC (Model-View-Controller) is a pattern in software design commonly used to implement user interfaces (VIEW), data (MODEL), and controlling logic (CONTROLLER). It emphasizes a separation between the software's business logic and display.

In Our Project this will be : Model - Database Schema's and Business logics and rules View - Server Side Templates (or React front-end) Controller - functions attached to routes for modifying request and sending responses. It's a link between the Model and View.

Router

These are like mini-application on which you can make set of Routes independently.
Routers can be attached to main Server App using server.use(router)
Arrange Directory in Server like this :

Controllers - file containing functions which are attached to each route path Routes - files containing routers Models : to be discussed in later chapters Views: to be discussed in later chapters

[[ Assignments ]]
Assignment 1 : Read More about Model View Controller online, link given below.
Related Links/Videos
Model View Controller
Chapter 6 - MongoDB - Server / Mongo Shell (CLI) / Mongo Atlas
[[ Reading Material]]
MongoDB is NoSQL database which has a JSON like (BSON data) data storage.

Setting up Database Server and Connecting with Mongo Shell
After installing MongoDB community server package on your system - you will have to start the database server using command :

mongod
This will start MongoDB server on default port 27017. You might have to create a directory for storage in MongoDB - if server asks for storage directory

Once server is started - you can use mongo client to connect to local server

mongo
Now you can use several commands to work with database:

show dbs
This will list all the database in your system

use <dbname>
This will command will let you switch to a particular

Understanding MongoDB structure
Hostname
Database
Collection
Document
Hostname is Database server address - like localhost or db.xy.com. In mongoDB hostname generally uses mongodb protocol to connect. So URLs are generally are of shape : mongodb://localhost:27017

Database are topmost storage level of your data - mostly each application has 1 database - however complex application might have more than 1 databases. Database is something like university database

There can be many collections inside a database - collection is a group of documents of similar kind - students, teachers, courses etc

Finally document is basic entity of storage in Mongod, it looks very similar to an object in JSON. (However it is BSON)

MONGO CLI
Mongo DB community server comes with in-bulit Mongo CLI which can act as a terminal based client. You can use the CRUD functionality from here

Read the commands here

Assignment 1
Try these commands given in Mongo CLI reference docs.
Show database
Use database
Show collection
Create Query (insertOne, insertMany)
Read Query (find, findOne)
Update Query (updateOne)
Delete Query (deleteOne, deleteMany)
Delete database (drop)
Assignment 2
Mongodump and Mongorestore
These utilities comes with community server and can be found in CMD/terminal. They are not the part of Mongo CLI client.

Mongodump command is used to take backup of complete database or some collections
mongodump  --db accounts 
Above command takes backup of database accounts and stores into a directory named dump

Mongorestore command is used to restore database
mongorestore --db accounts dump/accounts
Above command restore your database accounts from backup directory dump

Task : Use these commands on terminal/CMD (not inside mongo client)

Take a backup of database you created in assignment 1.

Restore the backup of database from dump directory.

Using MONGODB NODE.JS DRIVER [ OPTIONAL READING - as we will not use Mongo Driver ]
To install MONGODB NODE.JS DRIVER use this command

npm install mongodb
You can setup database in Node server using following commands :

const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');

// Connection URL
const url = 'mongodb://localhost:27017';

// Database Name
const dbName = 'myproject';

// Use connect method to connect to the Server
MongoClient.connect(url, function(err, client) {
  assert.equal(null, err);
  console.log("Connected correctly to server");

  const db = client.db(dbName);

});
Now this db handle can be used to perform any CRUD operation using MongoDB NodeJS driver.

CRUD Functions links
Create - Shell Version / Node Version
Read - Shell Version / Node Version
Update - Shell Version / Node Version
Delete - Shell Version / Node Version
[[ Chapter Notes ]]
Mongo Server

You can install MongoDB community server for your system and set the Path to bin folder
You can choose your own database path while starting the mongod server
 mongod --dbpath <path-to-db-directory>
Mongo Compass : UI Client to see mongo server (local or remote)

Mongo Shell : Command-line based mongo client for checking mongo database.

Some Mongo Commands:

Top Level commands :
(run from anywhere inside the shell)

show dbs;
use < database-name > - to choose a database and go inside its prompt
Database CRUD commands :
(run only from inside a database)

CREATE COMMANDS
db.< collectionName >.insertOne( newDocument )
db.< collectionName >.insertMany( documentArray )
READ COMMANDS
db.< collectionName >.find( filterObject ) - to read all docs
db.< collectionName >.findOne( filterObject ) - to read one document
db.< collectionName >.countDocuments( filterObject ) - shows total number of documents.
filter Object : { fieldName : {operator: value}} fieldName : database fields name operator : $eq = equal , $gt= greater than, $lt : less than, $gte = greater than equal, $and and $or operator value : what value we are comparing with operator.

e.g { age : {$gt:5}}. - age is greater than value 5

Cursor functions : These are applied to find() query .

sort( {fieldName: 1}) : 1 for ascending -1 for descending
limit( x ) : only gives x documents
UPDATE COMMANDS
db.< collectionName >.updateOne( filterObject, updateObject, options )
update Objects = { $set : {field: value}}
options : {upsert: true}
Upsert : Update + Insert, when we want a new info to create a new obejcts if no existing object matches filter queries.

db.< collectionName >.replaceOne( filterObject, updateObject ) Overwrites other fields also which are not in updateObject.
DELETE COMMANDS
db.< collectionName >.deleteOne( filterObject )
Projection

Only return selected fields while returning result documents.
db.< collectionName >.find( filterObject, projectionObject ) e.g. {name:1, age:1, id:0} - only show name and age and don't show id
MONGO ATLAS CLOUD SETUP : Check the video in tutorial

** Enviroment Variable** : To use environment variable we can use a npm package called dotenv which will create new process.env variables.

Install dotenv using npm install dotenv
just have use .env file in your root directory
and call require('dotenv').config()
Related Links/Videos
Mongo Atlas Setup Detailed Video

Chapter 7 - Mongoose and REST APIs
[[ Reading Material ]]
You can install mongoose using npm :

npm install mongoose
After installing , you can import mongoose to your project :

const mongoose = require("mongoose");
Connection to Database
To connect mongoose to your database test, you have to use the following commands :

var mongoose = require('mongoose');
await mongoose.connect('mongodb://127.0.0.1:27017/test');
Connection can also be stored in a variable to check whether it is connected properly or not. Also to disconnect database later on. You can read more details Here

Schema
Schema is the specification according to which data object is created in Database.

taskSchema which contains title, status, date fields. So every task object saved in database will have these 3 fields according to Schema given

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const taskSchema = new Schema({
    title:  String,
    status: Boolean,
    date: { type: Date, default: Date.now }    
  });
Many types of data are allowed in Mongoose Schema. The common SchemaTypes are:

String
Number
Date
Boolean
Mixed
ObjectId
Array
You can put a lot of conditions inside the Schema object :

    age: { type: Number, default:18, min: 18, max: 65, required :true }
    // default value of Number is 18 and should be between 18-65, and can't be null or empty
Detailed information on SchemaTypes is Here

Model
Model are similar to classes, they create a Class from Schema. These classes(i.e Models) can be used to create each new database object.

const mongoose = require('mongoose');
const { Schema } =  mongoose;

const taskSchema = new Schema({
    title:  String,
    status: Boolean,
    date: { type: Date, default: Date.now },    
  });
  
const Task = mongoose.model('Task', taskSchema);  //Task Model to create new database objects for `tasks` Collection
Task 1
Connect mongoose to a database named todolist if you don't have a database with this name. Mongoose will create it after you perform any insert operation.

Creata a Schema named taskSchema and model named Task as shown above.

CRUD in Mongoose
Create - new objects
To Create new obejct in database we can use new keyword and create an object from Model. We can use save() function to save the object in database. Unless, you call save function - the object remains in memory. If your collection not yet created in MongoDB, it will created with name of Model pluralized (e.g Task will make a collection named tasks)

server.post("/task",function(req,res){
    let task = new Task();

    task.title = "shopping";
    task.status = true;
    task.date = new Date();

    task.save();
})
Task 2
You have to create an API Endpoint to type POST named /task. It will create a new task item in database whenever called properly. All 3 fields title, status, date must be mandatory (required). If someone is not passing all fields properly, no database entry should be created.

//request body :

{
    "title" : "task1",
    "status" : true,
    "date" :'2010-05-30"     

}

// response body should return the newly created object.

res.json(task);
Check using Mongo Compass/or Mongo Shell that new record in database is created. Also check name of collection. Is is tasks ?

Read objects
To read new obejcts from database, one can use find query or similar queries. find queries also contain some conditions which can restrict what kind of data objects you want to read from database.

server.get("/task/:name",function(req,res){
    Task.findOne({name:req.params.name},function(err,doc){
        console.log(doc)  // this will contain db object
    })
})


server.get("/tasks",function(req,res){
    Task.find({},function(err,docs){
        console.log(docs)  // this is an array which contains all task objects
    })
})
Task 3
You have to create an API Endpoint to type GET named /tasks. It will return all task available in collection tasks.

//request is GET so no data in body :


// response body should return the all db objects of collection tasks.

res.json(tasks);
Check Mongo Compass/or Mongo Shell - if all records are returned in response. How you will change this API to make it return only one database record in which title is matched with title sent in request query.

Update - existing objects
To Update an existing object in database we need to first find an object from database and then update in database. This might be considered as a combination of find and save methods.

There are generally 2 cases in update :

Updating all values and overwriting the object properties completely.
Updating only few values by setting their new values.
First scenario is covered using this query. Here you are overwriting all properties and resulting object will only have name property.

server.put("/task/:name",function(req,res){
    Task.findOneAndReplace({name:req.params.name},{name:'YouStart'},{new:true},function(err,doc){
        console.log(doc)  // this will contain new db object
    })
})
Second scenario is covered using this query. Here you are only changing value of name property in existing object without changing other values in Object.

server.put("/task/:name",function(req,res){
    Task.findOneAndUpdate({name:req.params.name},{name:'YouStart'},,{new:true},function(err,doc){
        console.log(doc)  // this will contain db object
    })
})
Task 4
You have to create an API Endpoint to type PUT named /task/:id. It will update existing task item in database which has ObjectId set to id you have passed.

//request params will have id in URL path :

{
    "title" : "task-changed",
}

// response body should return the newly updated object.

res.json(task);
Check using Mongo Compass/or Mongo Shell that only title of record in database is changed. All other properties remain the same.

Delete - existing objects
To Delete existing object from database we need to first find an object from database and then delete. This might be considered as a combination of find and delete methods.

server.delete("/task/:name",function(req,res){
    Task.findOneAndDelete({name:req.params.name},function(err,doc){
        console.log(doc)  // this will contain deleted object object
    })
})
Task 5
You have to create an API Endpoint to type DELETE named /task/:id. It will delete existing task item in database which has ObjectId set to id you have passed.

//request params will have id in URL path :

// response body should return the deleted object.

res.json(task);
Check using Mongo Compass/or Mongo Shell that the record is deleted or not.

[[ Chapter Notes ]]
install mongoose npm install mongoose
Mongoose connection code
main().catch(err => console.log(err));

async function main() {
  await mongoose.connect('mongodb://127.0.0.1:27017/test');
  
  // use `await mongoose.connect('mongodb://user:password@127.0.0.1:27017/test');` if your database has auth enabled
}
Mongoose Schema : Each schema maps to a MongoDB collection and defines the shape of the documents within that collection.
const  productSchema  =  new  Schema({

title: {type:  String, required:  true, unique:  true} ,
description:  String,
price: {type:  Number, min:[0,'wrong price'],required:  true},
discountPercentage: {type:  Number, min:[0,'wrong min discount'], max:[50,'wrong max discount']},
rating: {type:  Number, min:[0,'wrong min rating'], max:[5,'wrong max rating']},
brand: {type:  String,required:  true},
category: {type:  String, required:  true},
thumbnail: {type:  String, required:  true},
images: [ String ]

});
Mongoose Model : model are built using a combination of Schema and name of Collection.
const Product  =  mongoose.model('Product', productSchema);
Mongoose Document - its is instance of a model. so Model is like a class and documents are like its objects. These documents are directly saved in mongoDB.
  const document = new Product();
 // document is actually saved in database after save()
  await document.save();
Mongoose Schema/Model can act as Model of Model-View-Controller concept.

CRUD API and mongoose methods
CREATE :

create product - use **POST ** HTTP Method
   const product = new Product();
   await product.save()
READ :

read all products - use GET HTTP Method
const  products  =  await  Product.find();

const  products  =  await  Product.find({price:{$gt:500}});
read 1 product - use GET HTTP Method
const  product  =  await  Product.findById(id);
UPDATE :

replace product fields (all fields) - use PUT HTTP Method
const  doc  =  await  Product.findOneAndReplace({_id:id},req.body,{new:true})
update only some product fields - use PATCH HTTP Method
const  doc  =  await  Product.findOneAndUpdate({_id:id},req.body,{new:true})
DELETE :

delete 1 product - use DELETE HTTP Method
const  doc  =  await  Product.findOneAndDelete({_id:id})
[[ Assignments ]]
Assignment 1 : Make a Schema for user with userSchema which has these conditions :

firstName is required, maximum length 16 chars
lastName is not required, maximum length 16 chars
age is a Number, minimum value 12, maximum 100
email make a validator of email, as given in mongoose documentation.
address make address a nested data structure which has its own Schema [ AddressSchema ??] [ Hint: check mongoose documentation for sub-documents to do it
Create addressSchema needed in above example as :

pincode : Number, required
street : String, required
phone: String, length=10
Now try to create this user object and save it to database.

What happens to addresses ? How address document is stored ? check if it creates a new collection in database
What happens if you don't provide validated data in any field. [Note: Throw proper errors strings ]
Related Links/Videos
Queries in Mongoose : Link

Chapter 8 - React Integration and MERN Stack Live deployment
[[ Chapter Notes ]]
Sending data from front-end to Server

Fetch : it is in-built API in the browser
Axios : we will use axios as it is easier to use.
CORS Issues :

CORS - Cross-Origin Resource Sharing (CORS) is a standard that allows a server to relax the same-origin policy

we will use CORS package to allow cross origin request from React JS server to NodeJS server as they are on different hosts.
npm install cors
to use cors -
const cors = require('cors');

server.use(cors())
HTML Forms

name attribute on input elements is used to send data keys which are validated with schema in backend.
Build a React Project :
Run npm run build
use build folder to be hosted on public hosting/static hosting
Host a React Project :
you can use build folder of react and add it to static hosting of express. server.use(express.static('build'));

Use Routing in Front-end
use wildcard in express route to point to React single page applications (index.html)

res.sendFile(path.resolve(__dirname,'build','index.html'))
__dirname is a variable

Assignments are after Chapter 9
Chapter 9 - Deploy Live
[[ Chapter Notes ]]
Preparation for deployment

First check whether front-end routes are independent of server, and make all of them relative to /
Connect MongoDB atlas - in-place of mongo local database
How to Deploy to Vercel :
Commit you code on a github account (personal account for free services)
Set Environment Variables on Vercel - like MONGO_URL, PUBLIC_DIR
Put a vercel config file - vercel.json in your project root directory.
After every change, commit your changes - and push code on github.
You have to provide permission for github directory to vercel. It will pickup vercel.json and package.json and deploy your code accordingly.
Check video for more details.
[[ Assignments ]]
Assignment 1 : Deploy your own application or API only to a live server like Vercel
Assignment 2 [Challenge] : Deploy your own application or API only to a live server Railway.app
Related Links/Videos
Heroku Deployment Video
Git Crash Course
Chapter 10 - Server Side Rendering
[[ Chapter Notes ]]
Server side rendering is done using many templating languages

EJS
Pug
Handlebars
We have used EJS which is one of the most popular one.

Install npm install ejs

Control flow with <% %>
Escaped output with <%= %> (escape function configurable)
<% if (product) { %>
 <h2><%= product.title %></h2>
<% } %>
For passing variable to template engine and render a new page :

const ejs = require('ejs');


ejs.renderFile(path.resolve(__dirname,'../pages/index.ejs'), {products:products}, function(err, str){
    res.send(str); // this is the rendered HTML
});
How to send HTML FORM data to Express
You need to have input boxes have proper name which will be used as key to objects sent to backend. Mostly in form like name=value
use action or for API destination action="/products"
use method or for API type method="POST"
use enctype with value application/x-form-urlencoded
[[ Assignments ]]
Assignment 1 : Create Server rendered page for quotes collection created in 1 of previous assignment. Use a very simple HTML template to display each quote in a list format. You can use other render method of EJS for this task. (not renderFile)
Related Links/Videos
DOM Series
Chapter 11 - Authentication with JWT
Using JWT for generating Auth Tokens
JWT library installation
	`npm install jsonwebtoken`
Use jwt.io to understand 3 parts of JWT - headers, payload, signature
Signing of JWT
jwt.sign(payload, secret) this returns a token

verifying a JWT token
jwt.verify(token, secret) this returns decoded value of payload

We will use HTTP Authorization headers for exchanging these tokens e.g. Authorization = 'Bearer JWT_TOKEN_VALUE'

Using RSA algorithm (public-private key) : check video.

Password Hashing
you can use a library like bcrypt to hash password, so they are not stored in plain text format

Installation :
npm install bcrypt

Hashing
bcrypt.hashSync(userProvidedPassword, saltRounds)

Verifying Password
bcrypt.compareSync(loginPassword, AlreadyHashedPassword)

return true of false based on verification of password

[[ Assignments ]]
Assignment 1 : Try to make a application which stores JWT in localstorage. So that even after you close browser and open site again. Server will still remember you JWT and authenticates you.
Related Links/Videos
Localstorage
SESSION MIDDLEWARE [Optional]
Check Video on Session :

Session middleware is used to store session variable for each user on server side. This middleware can make use of any data storage depending on settings. By default it stores session variables in Memory (RAM).

First install express-session middleware

npm install express-session
Now you can use it in your express server

var server = express()
const session = require('express-session')


server.use(session({
  secret: 'keyboard cat',
  resave: false,
  saveUninitialized: true,
  cookie: { secure: false }   // make secure : true incase you are using HTTPS
}))
Now you can use req.session object to store any value for a particular user in server session. This value will not interact with similar variable of other users.

server.get('/user', function(req, res) {
  if (req.session.views) {
    req.session.views++
    res.json({views:req.session.views})
  } else {
    req.session.views = 1
    res.send('welcome to the session demo. refresh!')
  }
})
Assignment for Sessions
In above example we are initializing a variable session for each user. Write similar code in your server

Checkout if its value increases every time you refresh the page.
What happens when you open URL in another tab.
What happens when you open URL in another browser
More Interesting ways of Authentication :
Passport JS Authentication
Chapter 12 - Mongoose Advanced queries, Node Streams, Events etc.
[[ Chapter Notes ]]
Mongoose Queries
Sorting:

find().sort({fieldname: 1}) // ascending can be 1, asc, ascending , Descending values can be -1, desc, descending

Pagination related queries:

find().limit(pageSize).skip( pageSize*(pageNumber-1)) // where pageSize is number of document results you want to show.

Population

Populate() lets you reference documents in other collections.

const  userSchema  =  new  Schema({
firstName: { type:  String, required:  true },
lastName:  String,
cart:[{ type:  Schema.Types.ObjectId, ref:  'Product' }],
email: {
    type:  String,
    unique:  true,
    validate: {
       validator:  function (v) {
        return /^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$/.test(v);
          },
       message: (props) =>  `${props.value} is not a valid email!`,
     },
    required:  true,
},
password: { type:  String, minLength:  6, required:  true },
token:  String,
});

//cart populated example
const  user  =  await  User.findById(id).populate('cart');
For More details : Detailed Population Video

Node Events and Event Emitter
const em = new EventEmitter()

em.on(eventName, (payloadData)=>{} ) // listeners

em.emit( eventName , payloadData ) // emit events
Node Streams
A readable stream

const  rr  =  fs.createReadStream('./data.json');

rr.on('data', (data) => { // received data event on every file read
 console.log({data});
});

rr.on('end', (data) => {  // received end of stream event
 console.log({data});
});
Socket in Node (Socket.IO)
Install Socket IO library
npm install socket.io

Server Side Code
const  server  =  express();
const  app  =  require('http').createServer(server);
const  io  =  require('socket.io')(app);

io.on('connection', (socket) => {
console.log('socket',socket.id)

socket.on('msg',(data)=>{ // listener to client-side events 'msg'
console.log({data})
})
socket.emit('serverMsg',{server:'hi'} //emitting 'serverMsg' for Client-side
});

app.listen(port)
Client Side Code
// embeding client-side library which will be downloaded from module installed on Server
<script  src="/socket.io/socket.io.js"></script>

<script>
const  socket  =  io();
console.log('socket',socket.id)

socket.emit('msg',{player:'one'}) // emitting 'msg' to server-side

socket.on('serverMsg',(data)=>{  // listener to server-side events 'serverMsg'
   console.log({data});
})

</script>
Uploading a file on NodeJS
Uploading a file using Multer middleware Video
[[ Assignments ]]
Assignment 1 :
Make a simple group chat application using Socket.io library.
You need to have a user enter their name in textbox (you can store that in localstorage)
After user enters the name : they can see a text box where they can start entering the text messages.
Display messages from user and others in a simple html list format.
You can align incoming messages from other users to left and your own messages to right side.
Optionally, you can use database to store the old text messages in case you want old chat to be reloaded.
------------END OF COURSE---------------------

MERN STACK PROJECT IDEAS
1. Resume/Profile Create Web application
An online resume generator application will able to generate resume for students and professional based on their input data. We will have options of downloading the resume or hosting the resume on a particular URL (which user can share). Users will be able to choose between many Template designs for their resume. User data will be stored in database and can be edited later on.

User Login (Social Logins)
Saving user info using validated forms
HTML/CSS based templates to design different style of resumes
PDF generation of completed resume
Providing link on online resume of a person (HTML version / PDF version)
2. Online Tic Tac Toe
Tic Tac Toe is quite ubiquitous popular game. We have a 3 x 3 grid with traditional cross and circle notation. However playing tic tac toe with a distant friend connected via social media is a dream come true. Here is the simple game :

Connect with Facebook/Google Login for user Identity.
Find all people logged in via Facebook on this application
Challenge someone to play with you.
Have a separate scorecard for each pair of users.
show world leaderboard - where you can have your algorithms to show chart toppers - may be number or wins or win/lose ratio.
UI should be simple and understandable.
Use of animation is preferable but should not be too much
Mobile friendliness is required
Sounds are optional but can add a lot to the game.
3. E-commerce Application
An Amazon like store to find and buy things. The site will have to interface one for admin and other for general users :

User site features :

User must be able to search product via name/ category etc.
Each item will belong to atleast one category of items (like electronics)
Each item will have some fields - name, price, description, image etc.
User can sort items by any field - name , price etc.
Cart will have features to add item, remove item, change item quantity, show total etc.
User order will be saved in database.
User can check details of their old orders.
Admin site features :

Admin must login using a secret password.
Admin panel should show you list of all available products with their available quanities.
Admin can add new items to store or delete old items. You can optionally provide them access to edit item details.
Admin can update quantity of any item.
4. Photogram
PhotoGram Project is a web app similar to instagram. Purpose of app is to store your photos in an album and add some filters. Users can login and browse their old photos, search them by name, sort using name/date added etc. They can also apply instagram style filters to their photos.

Features :

The user can sign up and create a new account. Check for email duplicate scenario and show an appropriate message if the same email is used for login.
The user can log in using the previous email/password combination. If email/pass is incorrect to show the appropriate error.
If the user successfully creates a new account take him to create a new post form - which will have fields photo, caption etc. Date will also be stored in database along with these information.
After submitting the above form user should automatically be redirected/routed to the photo Gallery page.
Gallery page should show all cards of logged in user. Only photos uploaded by the same user must be displayed.
If user login into existing account he must be redirected to Gallery page if he has 1 or more cards uploaded. If no cards are there he must be redirected to the same form as after signup.
Gallery page should also have a link to form page - using button - “Create new card”.
The user can also delete cards from gallery page by click on a cross Icon “X” which you can add to all cards in front-end.
To maintained loggedIn user use sessions and localStorage.
5. Online Pokemon
PokeMon requires your help. Save them by picking the right ones. There are some good characters and there are the bad ones. Create a 8×8 Div to make a gameboard.

Game Rules (Offline)

Pikachu should appear at random places.
At the same time bad guy (giovanni) will also appear.
Pikachu and bad guy can’t be on same grid box.
You have to click Pikachu Grid to save it.
One correct click means +1
Consecutive 3 correct means +5 bonus also.
Wrong answer will mean a strike.
3 strikes in continuation means “Game Over”
A total of 30 points mean Level Complete.
1st Level will have Pikachu and Other Guy appearing for 2 second.
There will be a gap of 3 seconds in between next round.
With every increasing Level Pikachu and other will appear for lesser time. And gap of round will also be decreased after each Level.
Game Rules (Online)

All above rules will be applicable accept for their is no 'Game Over' and correct point is given to only the first person who click the pikachu.
6. Multi-User Chat Application
Multi-user chat will be a web application where users can chat privately or in group chat.

Google Login and Custom Login for users
User will see a whatapp web like interface on left hand side menu
Multi user group chat (For all logged in users)
File sharing and File upload
Chat Room Should be accessed via name credentials ( later on social login)
You can upload a picture in your profile
You can change profile settings
All online users should be shown in side pane
click on a user to selectively chat with him/her
Group chat should be visible to all
Provide theme color to user which will be used as there chat text also
Allow #tag feature where one can tag a statement which be later searched on via a search box
Search box should be able to search all text, usernames
Time stamp must be visible in Chat (in form of time Ago)
Chat should auto scroll to lowest part
Use filters to filter out any blacklisted words
Block user based on use of blacklisted words
See the chat from where you have left
only show last 100 messages and load old ones on demand via a scroll function.
Use a sound directive for special characters
7. Medical Chatbot
Chat bots are the need of the time. With too much information overload and lots of application to interact with - humans need a way to interact with devices in more human way. Chat bots makes your life easy by putting up intelligent question, suggestions and making choice simple enough. We are designing a chat bot which may diagnose simple disease or common problem with health.

Chatbot should be invoked as soon as you open the website
Chatbot should provide few options for any questions you put up
By navigation through choices you should be able to reach to final search results.
Chat bot should start with category of malice you have and then dive into details of each
You can categorize few common symptoms like headache, flus and food allergies.
This app will not recommend any medicine but can recommend simple cure which are available in household.
8. Quiz / Online exam Application
Admin Panel

Add a question
Edit a question
Remove question
Change the order of questions(Move the questions up or down)
Choose the type of answer for the question(short answer, long answer, MCQ etc.)
Time limit for a question
Time limit for the test
Negative marking
Choose randomization of questions for adjacent systems
Choose different question for different students(Set - A,B,C,D)
Save the state of answers and auto submit at the end of test if the student has not submitted the test himself
Making test go live after editted in private mode.
Examinee side

Login
One question per page.
Mark a question as “remind me” later
Show overall progress which show attempted / unattempted questions.
Timer showing the timing remains or time completed
Submit paper at end of time automatically.
Manual submit option.
9. Party/Trip Expense planner
This app can be used to manage expenses between friends who are planning an event/trip/party. This app will help in adding all expenses done by any individual. It will provide the report of who owes how much and money should be given to whom.

Features :

Social login
Creating a group of friends who have account on this app.
Make a new event/trip (name of event)
Adding entries of money given by individuals. (Who paid, for what, how much)
Updating any old entry (but with having updated date shown and count of updated version)
Deleting entry by confirmation of multiple users.
Functionality to end the event - so no new entries can be made.
Functionality to show who owes and who should get the money.
Automating mails and messages to every member about how much they owe or will get at end of trip.
10. Map Based Spot Add/Search
Create a spatial database for adding and searching your favorite place on map.
You can take a city map via google map Api.
Coordinates should be marked with extra information stored on your own database.
One should be able to add points on map via clicking on map and filling a simple form.
Form must contain name of place, description and category of place like (Cafe, restaurant etc.)
Also you can represent you places with some icons on map.
In Search Section, one must be able to search places according to category, distance from you, name of the place etc.
Results must be arranged according to relevance and then according to distance from you. For e.g a direct name matching should be of higher priority to that of distance of that place. But in case someone is searching by category names one should prefer to go by distance.
In Search, If somebody click on a place they must get a small info box about the place.
In Search, if somebody clicks on a place there must be a provision to get direction which must redirect to google maps application for exact direction. Note : you don’t need to integrate google maps in your application for this. Just redirect them in another tab or app.
Only admin can edit place in the account, admin account should be kept secret.
Search must be available to all people. However they can give feedback about the place but that will only be visible after approved by admin.
11. Calendar Reminders App:
Create a todo list application with a Nice UI
You can add/remove tasks etc.
which should have task with given date and time
Use system date and time pickers
Each task will have some starting time which should integrate with your system calendar.(Google calendar)
Whenever task is pending system will reminds you through calendar app or email or SMS (you can choose notification preferences)
12. Pomodoro App (Time Management)
Create a todo list styled task your perform daily like Reading, Jogging, cooking etc.
Track every task in terms of pomodoro breaks ( 1break 25 min)
After 4 short break take a long break
Pomodoro Timer should be circular and it should raise and alarm after time is over.
You can take a break and start pomodoro timer again on same task or differs task
Your list will show how many pomodoro times you have given to each task
Refer to this URL

https://zapier.com/blog/best-pomodoro-apps/

13. Popular content search engine and pinboard
Use #hashtags to search content through many social apps like facebook, instagram, twitter, reddit etc.
Sort by popularity
Show different media into one list - images, videos, status etc.
Bookmark content for making collections and pins
You can save items in diff boards - sports, tech, weather, politics
14. Buy/Sell App
Login
Sign up - Ask for interested in buying or selling or both
Messages/offers for buy
Push notifications for any buy/ sell offer
category of item
negotiable / non negotiable
send an offer
mark as favorite
15. Table Booking system
When you visit a restaurant you have to book a table for people. If you book in advance, restaurant has to plan according to available options.

Choose restaurnt
Auto detect location and resturant nearby sorted by distance
filter - number of persons, pure veg, cuisines, ratings etc.
Book seats
On restaurant side they will have a limited number of seats.
Show how many seats are available now.
If seats are over disable booking at restaurant
Admin panel : Can login into restaurant and change number of seats available
16. Book Search Engine
Login to account,
ratings,
add/ edit / delete a review,
the social reading graph
recommendations of books
Author’s information
user’s information -
search book by title / ISBN / author
read reviews of a book by providing its title / ISBN / author
read/write comment for a book
Follow / unfollow an author
Follow/ unfollow other users
Find a group
Join a particular group
Create a new group
Like / unlike a resource
Add/ edit / delete a book shelf
add /delete books to book shelf
User’s read status- set status and get any user’s status
17. URL shortner App
generator a short url
redirect to the main webpage
track how many people visited that url
how many clicked on the short url and navigated to the designated page
which device they used - mobile / desktop
optional - require a user to log in to view private url
18. Movie Recommendation based on IMDB rating
search for movies by title
get all the episodes of any TV series.
get year of release of a movie
get rating of movie
get movie by genre
get movie by release year
get movie by actors
19. Railway App (PNR checking & Live running status)
login
add my journey details (PNR)
get current PNR status
push notifications on day of journey
set timing for reminder - a day before, an hour before etc.
get train running live status by API
20. Blog Application
Login
Create a new blog - image, title, text content (rich text containing HTML based content)
Use can see list of their own blogs and can delete any old blog.
Show list of blogs in home page with card format.
You can see your blogs and everyone else blog on home page
Sort blogs by author, date created etc.
Create category of blogs and classify blogs under a catgeory.
Create option to share blog via social media.
Create like feature for blog. A use can one like once for same blog.
21. Notes Application
User can login
Make a note making application similar to Google Keep.
User can make a board in which they can add some notes. Boards are like study, watch, books etc.
User can make text notes, add images and files attachements also.
User can change card color according to priority of tasks (Red, yellow, green)
User can update and delete cards.
User can search cards with text search.
22. Currency Converter App
Show a list of top currencies and countries sorted by their value for today.
List of countries will be displayed with their flag icons. Example UI Link
There should be two input "Current Currency" and "Exchange Currency". e.g Current Currecy as "INR" and Exchange Currency as "USD".
Automatic conversion should be done on change of any change in Dropdown menus.
You can reverse the currency options by simple click.
Application should store old conversion records and create a simple list of it.
23. Appointment booking app
Appointment book app creates and event in which you can book slots. It can help a professional like doctor, interviewer to provide slots to other person in which they can visit. Calendly site is a good example of such an app

User can login
Creates an event with name / description/ Date. Start and endtime.
User chooses how long will be slots between start and end time. (10 mins).
Final user saves the event setting and gets a URL.
User shares the URL with all non logged in users.
These user can only see Name of the event, date, start time/endtime and available slots.
User books a slot by passing his email, name information.
If a slot is booked that will be removed from available slot list and other users will not be able to book the same slot.
If all slots are booked, users will be shown a message that no slot is available.
24. News application.
This news application will be something similar to google news and will pull news from major news channels and apis.

News will be categoriesed according to tags India, sports, world, movies etc.
News can be bookmarked by user for later reading.
User can search new according to their keywords.
Database will store old news items and they will also be searchable.
News will be sorted according to new to old.
25. Meme Genrator App
Make an advanced interface for creating memes! Allow the user to upload an image, write a caption, and build a meme with the Imgflip api. To take it to the next level, allow the user to share their meme on Twitter, Facebook, and other social platforms.

User should upload a image of some restricted dimension (max width fixed)
User can provide some caption to the image.
Captions can be changed in font-size, font-color and orientation.
Also one can move captions up or down in the image.
Finally user can generate the meme and get a final URL.
User can share the URL to other friends to show the meme.
As an extra feature one can provide download image feature to user.
26. Tetris Game
Example : Check this

27. Break Journey App
It is easy to make travel booking for direct journey from one city to another. But in case you don't find direct flights, trains etc. You might have to break the journey and find trains from a intermediate station and change from their to get to end destination.

User will provide start and end destination
User will provide a intermediate city from where they can change.
Interface will provide the connecting journey options on same date.
Care must be taken in timings of arrival and departure - so that one can continue the journey.
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Redux JS MasterClass
Hi, This is course page of CoderDost Youtube Channel Redux JS 2023 Course Video Link ,

How to use this code :
You can download code in 2 ways :
Git Commands
use git clone <repository_url>

checkout 'redux' branch - All Chapters are in same branch but different folders git checkout redux

run npm install inside the each folder before running the code

If you are not comfortable with git, directly download the branch as Zip.
Choose branch related to the Redux e.g. react. It contains all chapter

run npm install inside each chapter folder before running the code

Redux JS Series
Chapter 1 - Redux Concepts and Pattern
Assignment 1 : Using the concepts learnt in this chapter. Make a Async type of call from a new reducer to any online API like JSON Placeholder Posts. Also show proper loading messages in console. Like - loading posts..., posts loaded , posts fetching failed. Also add those posts to a state of reducer in a sorted manner (sort by title)

Assignment 2 : Check out IMMER library and run some example and see how you can make mutating updates like state.amount++ inside reducer logic. And still it work perfectly in redux. Immer Link

Related Videos
De-structuring Assignment : Long Video | Object De-structure Short Video | Array De-structure Short Video
Import/Export : Long Video | Short Video
Spread Operator : Long Video | Short Video
Callbacks
Promises
Async Await
Chapter 2 - Redux With React Application
Assignment 1 : Add more cases in Account Reducer called decrementByAmount . Also check that amount should not be decremented in case amount to be decremented is less than account Balance. For e.g. if total amount in account is 10, you can't decrement by 11. Also show an error in that situation to user.

Assignment 2 : Check out IMMER library and run some example and see how you can make mutating updates like state.amount++ inside reducer logic. And still it work perfectly in redux. Immer Link

Related Videos
React-Redux in Class Components
Chapter 3 - Redux Toolkit with React
Assignment 1 : Add more cases in Account Reducer called decrementByAmount . Also check that amount should not be decremented in case amount to be decremented is less than account Balance. For e.g. if total amount in account is 10, you can't decrement by 11. Also show an error in that situation to user.

Assignment 2 : Create more async thunk examples, we only tried GET USER- READ example. But try the CRUD example to Create new user, Update the user, Delete the user. - You have to create a list of users which has names of all users in local database - You an INPUT BOX to add new users to list , users show also add to database and updated in list.[Hint: use REST API concepts for Create API, POST method] - You can put a delete button on end of list item. On clicking of this button user list item will be deleted from database. [Hint: use REST API concepts Delete API, DELETE method] - You can put a selected button on end of list item. On clicking of this button user list item will change colors. [Hint: use REST API concepts Update API, PUT/PATCH method] -

Related Videos
REST API concepts
REST API complete explanation in NodeJS
Chapter 4 - Redux Toolkit Query
Chapter 5 - Redux Toolkit with Async Thunk - Product and Cart Project
Assignment 1 : Add a <Select> on Product Card also which shows quantity selector, So user can add item with a particular quantity also initially.
Assignment 2 : Change the <Select> on Cart Items to + and - buttons which should increment or decrement quantity of item in the cart. Also check if Cart total is coming correct.
Chapter 6 - Redux Saga Introduction [Optional chapter]
Assignment 1 : Complete the delete and update feature using Redux Saga middleware