is there a mongoose connect error callback

user_388026 0
Viewed 64933

how can i set a callback for the error handling if mongoose isn't able to connect to my DB?

i know of

connection.on('open', function () { ... });

but is there something like

connection.on('error', function (err) { ... });

?

mongoose node.js mongodb javascript
6 Answers

As we can see on the mongoose documentation for Error Handling, since the connect() method returns a Promise, the promise catch is the option to use with a mongoose connection.

So, to handle initial connection errors, you should use .catch() or try/catch with async/await.

In this way, we have two options:

Using the .catch() method:

mongoose.connect('mongodb://localhost:27017/test', { useNewUrlParser: true })
.catch(error => console.error(error));

or using try/catch:

try {
    await mongoose.connect('mongodb://localhost:27017/test', { useNewUrlParser: true });
} catch (error) {
    console.error(error);
}

IMHO, I think that using catch is a cleaner way.

user_41575890
  • Handle (catch) the connect exceptions
  • Handle other connection errors
  • show a message when successfully connected
mongoose.connect(
  "mongodb://..."
).catch((e) => {
  console.log("error connecting to mongoose!");
});
mongoose.connection.on("error", (e) => {
  console.log("mongo connect error!");
});
mongoose.connection.on("connected", () => {
  console.log("connected to mongo");
});
user_47184340
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