Unable to connect with Mongoose (Mongodb) - reactjs

Question

const express=require('express');
const mongoose=require('mongoose');
const morgan=require('morgan');
const path=require('path');
const app = express();
const PORT = process.env.PORT || 8080;
mongoose.connect('mongodb://localhost/SUCCESS', {
useNewUrlParser: true,
useUnifiedTopology: true
});
mongoose.connection.on('connected', () => {
console.log('Mongoose is connected');
})
//HTTP request logger
app.use(morgan('tiny'));
//Routes
app.get('/', (req, res) => {
const data = {
username: 'caa',
age: 5
};
res.json(data);
});
app.get('/api/name', (req, res) => {
const data = {
username: 'caa',
age: 5
};
res.json(data);
});
app.listen(PORT, console.log(`Server is starting at ${PORT}`));
node pages/server.js
Server is starting at 8080
(node:6253) UnhandledPromiseRejectionWarning: MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017
at new MongooseServerSelectionError (/Users/Abc/Desktop/success/node_modules/mongoose/lib/error/serverSelection.js:22:11)
at NativeConnection.Connection.openUri (/Users/Abc/Desktop/success/node_modules/mongoose/lib/connection.js:808:32)
at Mongoose.connect (/Users/Abc/Desktop/success/node_modules/mongoose/lib/index.js:333:15)
at Object.<anonymous> (/Users/Abc/Desktop/success/pages/server.js:18:10)
at Module._compile (internal/modules/cjs/loader.js:1158:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1178:10)
at Module.load (internal/modules/cjs/loader.js:1002:32)
at Function.Module._load (internal/modules/cjs/loader.js:901:14)
at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:74:12)
at internal/main/run_main_module.js:18:47
(node:6253) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:6253) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Answer 1

I had the same issue. Please update your code like this.
mongoose.connect("mongodb://127.0.0.1:27017/SUCCESS",{
useCreateIndex:true,
useNewUrlParser: true,
useUnifiedTopology: true}).then(()=> {
console.log('Database Successfully Connected')},error =>{
console.log(error)})
As next step,
Go to your Task Manager
Services
Start 'MongoDB'
Hope this will work.

Answer 2

// Seems like you did not define the default port of mangoose, Please refer below code
const mongoose = require('mongoose');
const db = "mongodb://localhost:27017/SUCCESS";
mongoose.connect(db, {
useCreateIndex:true,
useUnifiedTopology:true,
useNewUrlParser:true
}).then( () => {
console.log("Connected To Mongo Db DataBase");
}).catch((err) => {
console.log("DataBase Connection Error " + err);
})

Answer 3

I know I'm super late but this should fix it.
const db = mongoose.connect("mongodb://localhost/swag-shop",
{
useUnifiedTopology: true,
useNewUrlParser: true,
useCreateIndex: true,
}).then(() => {
console.log("Connected To Mongo Db DataBase");
}).catch((err) => {
console.log("DataBase Connection Error " + err);
});
then go to your powershell in windows or terminal in mac and type 'Mongod' and then create another tab in your terminal or open a another window of powershell and then type 'Mongo' and this should fix your problem.