[FIXED] How to connect mongoDB in react

Issue

Such a problem that when I try to simply connect mongoDB in react

import React, {Component} from 'react';

export default class App extends Component{

  componentDidMount(){
    const {MongoClient} = require('mongodb');

    const client = new MongoClient('mongodb+srv://dafu4k:****@cluster0.jd26aac.mongodb.net/?retryWrites=true&w=majority');

    const start = async () => {
    try{
        await client.connect();
        console.log('Connected')
    }
    catch(e){
      console.log(e)  
    }
  }
  start();
 }

  render(){
    
  return (

    <>
    <h1>Home page</h1>
    </>
  )

  }
}

Errors of the same type appear in the browser itself

Module not found: Error: Can't resolve 'os' in 'C:\Users\DaFu4\OneDrive\Рабочий >стол\mongotest\mongo-test\node_modules\ip\lib'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default. This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:

• add a fallback 'resolve.fallback: { "os": require.resolve("os-browserify/browser") }'
• install 'os-browserify' If you don't want to include a polyfill, you can use an empty module like this: resolve.fallback: { "os": false }

They differ in that the last line has different keys (timers,crypto,http, etc.)

I watched how to connect mongoDB to react, everywhere they used a certain mongoose along with mongoDB, but I can’t understand, maybe it’s required to connect to react, or am I still doing something wrong? (in normal js everything works fine, the code has not changed)

src/index.js

import React from 'react';
import ReactDOM from 'react-dom/client';

import App from './App';
const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>
);

package.json

{
  "name": "mongo-test",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.16.4",
    "@testing-library/react": "^13.3.0",
    "@testing-library/user-event": "^13.5.0",
    "crypto-browserify": "^3.12.0",
    "mongodb": "^4.7.0",
    "react": "^18.1.0",
    "react-dom": "^18.1.0",
    "react-scripts": "5.0.1",
    "web-vitals": "^2.1.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }
}

Solution

We can not connect React JS to MongoDB because things don’t work like this. First, we create a react app, and then for backend maintenance, we create API in node.js and express.js which is running at a different port and our react app running at a different port. for connecting React to the database (MongoDB) we integrate through API.

Check this link:

[1]: https://www.geeksforgeeks.org/how-to-connect-mongodb-with-reactjs/#:~:text=First%2C%20we%20create%20a%20react,MongoDB)%20we%20integrate%20through%20API.

Answered By - Sucheta Singha
Answer Checked By - - Mildred Charles (ReactFix Admin)