task-manager

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Task Manager Web App

• global is the object containing fucntions all round the environment

• setInterval(callback fun, time interval to repeat the callback fun)

• to stop the execution of the setInterval use setTimeout with clearInterval as a callback fun

• __dirname and __filename

• modules are encapsulated code that is to import and use in another code block - simply a js file

• default is the commonjs module using require function and parameter as the file location

• top level code in module will be executed and modeul.exports is assigned to the varibale where the require fucntion is called

• module.exports = variable/fun

• module.exports = { name1: name1 or name1, name2, }

• Core modules are predefined inside nodejs

• os module contains the details of the operating system

• path is another such package

• to make a server we need http module - core module

• http.createServer(callback fun) callback fun takes in req, res

• now listen to the server by defining the port and hostname finally a call back fun

• req is a ver big object

• create routes inside the createServer callback fun

• use res properties to decide what to do on which route

• res.url will tell the path of the page requested

• res.setHeader will display the text/html and Content-Type

• res.write will implement the html code written inside this write function call

• initialise the folder with npm to track the package changes

• npm init -y so that it will take the default values to the options asked

• create instance of express()

• similar to the node core modules - http to create a server express is used to create an express server

• express server is simpler to use than http module

• routes are established using app.get(route name, callback fun containing req, res)

• res.send is used to send the thing to the page

• nodemon is used to monitor the changes in the server and restart the server automatically

• nodemon is a local dependency i.e dev dependency so -D to install as dev dependency

• nodemon serverfilename

• to not run with the nodemon as a command embed that in the main key of package.json

• "main" : "serverfilename.js"

• inside scripts add

  start : "node filename.js" this is worked with deployment backend : "nodemon filename.js"

• now just use npm run start | backend

• http request methods - get | post | put / patch | delete

• get(read) : retrieve the data from the web server - frontend to backend

• post(create) : send data to server

• put / patch(update) : modify or update data on the server

• delete(delete) : delete data from the server

• *http response status codes

• Informational responses (100 - 199)

• Successful responses (200 - 299)

• Redirection messages (300 - 399)

• Client error responses (400 - 499)

• Server error responses (500 - 599)

• 200 request success

• 404 page not found

• install mongoose and dotenv to use the .env file values

• use seperation of concerns to make sure db schema and model file is seperated from the server.js

• connectonDB is preffered to be in the server.js as it may be simplified

• first connect to the db and only start the server

• while post request establishment is done

  done it either by middleware using next fun or do it using express module

• importing task model is used to do CRUD operations on the database

• create a .env file to store environment variables such as database connection strings

• use process.env.VARIABLE_NAME to access these variables in your code

• set up Mongoose schemas and models to define the structure of your data

• create routes for handling different HTTP requests (GET, POST, PUT, DELETE)

• use Express middleware for error handling and logging