How to fix Mongoose deprecation warning about "strictQuery"

Question

When I start build my backend server, I get this deprecation warning, but it's showing that I'm connected to the database.

File server.js

const dotenv = require('dotenv');
const mongoose = require('mongoose');
const app = express();
dotenv.config();

mongoose
  .connect(process.env.MONGODB_URI)
  .then(() => {
    console.log('connected to db');
  })
  .catch((err) => {
    console.log(err.message);
  });

const port = process.env.PORT || 5000;
app.listen(port, () => {
  console.log(`serve at http://localhost:${port}`);
});

File package.json

{
  "name": "backend",
  "version": "1.0.0",
  "description": "backend",
  "main": "server.js",
  "scripts": {
    "start": "node server",
    "dev": "nodemon server"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "dotenv": "^16.0.3",
    "express": "^4.18.2",
    "mongoose": "^6.8.0"
  },
  "devDependencies": {
    "nodemon": "^2.0.20"
  }
}

And this is the Mongoose deprecation warning:

Screenshot of Mongoose Deprecation Warning

It shows:

[MONGOOSE] DeprecationWarning: Mongoose: the `strictQuery` option will be switched back to `false` by default in Mongoose 7. 
Use `mongoose.set('strictQuery', false);` if you want to prepare for this change. 
Or use `mongoose.set('strictQuery', true);` to suppress this warning.
(Use `node --trace-deprecation ...` to show where the warning was created)

Answer 1

This warning was introduced to notify users about the change that will be introduced in Mongoose 7 to the default value of strictQuery.
It's default value will be brought back to false.

You can either set the strictQuery option to true globally to suppress the warning with:

const dotenv = require('dotenv');
const mongoose = require('mongoose');
const app = express();
dotenv.config();

mongoose.set('strictQuery', true);

Or, set the flag to false if you want to override the current strictQuery behavior and prepare for the new release:

const dotenv = require('dotenv');
const mongoose = require('mongoose');
const app = express();
dotenv.config();

mongoose.set('strictQuery', false);

Either way the warning should disappear.

For more information on why strictQuery will be brought back to false by default see here.
For more information on strictQuery see here.

Answer 2

Add mongoose.set('strictQuery', false); before connecting to the MongoDB server.

mongoose.set('strictQuery', false);
  const conn = await mongoose.connect(process.env.MONGO_URI, {
  useNewUrlParser: true,
 useUnifiedTopology: true,
});

Answer 3

Go to Network Access on your MongoDB page in the browser. Then click button Add IP address and add address "0.0.0.0".

It helps you to connect.

Answer 4

Mongoose supports a separate strictQuery option to avoid strict mode for query filters. This is because empty query filters cause Mongoose to return all documents in the model, which can cause issues.

Provide mongoose.set('strictQuery',true); to solve your issue

    const dotenv = require('dotenv');
const mongoose = require('mongoose');
const app = express();
dotenv.config();

mongoose.set('strictQuery', true);

mongoose
  .connect(process.env.MONGODB_URI)
  .then(() => {
    console.log('connected to db');
  })
  .catch((err) => {
    console.log(err.message);
  });

const port = process.env.PORT || 5000;
app.listen(port, () => {
  console.log(`serve at http://localhost:${port}`);
});

Answer 5

I added mongoose.set('strictQuery', true) then the message went away.

Answer 6

You can try it...

const dbSetup = async () => {
  try {
    const DBURL = process.env.DB_URL;
    mongoose.set("strictQuery", false);
    mongoose.connect(DBURL, {
      useNewUrlParser: true,
      ssl: true,
      sslValidate: false,
    });
  } catch (err) {
    console.log("Databse Connection Error : " + err.message);
  }
};