This is my nodejs code
const mongoose = require('mongoose');
function connectDB() {
//Database connection
mongoose.connect(process.env.MONGO_CONNECTION_URL, {
useNewUrlParser: true,
useCreateIndex: true,
useUnifiedTopology: true,
useFindAndModify: true
});
const connection = mongoose.connection;
connection.once('open', () => {
console.log('Database connected.');
}).catch(err => {
console.log('Connection failed.');
})
}
module.exports = connectDB;
Showing this err while I am trying to connect with server
}).catch(err => {
^
TypeError: connection.once(...).catch is not a function
Does it return a promise?
db.once('open', function(err, resp){
console.log(resp);
});
Or
mongoose.connection
.once('open', function () {
console.log('MongoDB running');
})
.on('error', function (err) {
console.log(err);
});
That means the once function does not return a promise object in the first place.
You can use catch with mongoose.connect to handle errors if there is any, check the example below:
function connectDB() {
//Database connection
mongoose.connect(
process.env.MONGO_CONNECTION_URL,
{
useNewUrlParser: true,
useCreateIndex: true,
useUnifiedTopology: true,
useFindAndModify: true
}
).catch(err => console.log(err.reason));;
const connection = mongoose.connection;
connection.once('open', () => {
console.log('Database connected.');
})
}