Getting Started with MERN | July 2023

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Follow below steps to get started

  1. Go to MongoDB cloud 
  2. create project with any name
  3. create a cluster 
  4. Now connect  with the compass by copying the string and pasting in compass 
  5. Inside compass create a database( which is your db name) and collection(this is your model name)
create two folders 
backend
frontend

In backend,

  • npm init -y
  • npm install express, mongoose, cors, nodemon, dotenv
  • now add this in scripts in package.json "start": "nodemon server.js"
  • npm install body-parser
  • npm install express-validator
In dotenv,
PORT = 3001
URI = "mongodb+srv://username:password@cluster0.sfkjwki.mongodb.net/learn_mern"

URI string will be obtained from Mongodb->cluster->connect->connect with compass....

In server.js add this to use .env
require("dotenv").config()
const port =  process.env.PORT
const uri =  process.env.URI

Note: 
 use app.use(express.json()); 
to avoid destructing problemss...

for running backend use: npm start

If everything is fine and still giving mongodb cannot connect then 
Go to Mongodb cloud and 
Navigate to Network Access and Add your Current IP address and restart the server
In your MERN application, when you are dealing with asynchronous operations like fetching data from a database (as in your previous question), you typically use .then() and .catch() to handle the asynchronous flow and potential errors. The try and catch blocks are often used for synchronous code or within async functions that use await.

try {

  // Code that might throw an error

  const result = someFunction();

} catch (error) {

  // Handle the error

  console.error('An error occurred:', error);

}

someAsyncFunction()
  .then((result) => {
    // Handle successful result
    console.log('Success:', result);
  })
  .catch((error) => {
    // Handle error
    console.error('An error occurred:', error);
  });

To validate our data going to db

npm i express-validator




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