MongoDB with Node.js Best Practices

Implement Connection Pooling

Modify a Node.js app to use a single MongoDB connection pool instead of opening new connections per request.

Expected output: Application reuses MongoDB connections efficiently without connection leaks.

Hint: Use Mongoose's connect method with poolSize option and share the connection instance.

Design a User Schema

Create a Mongoose schema for a user with fields: username (unique), email (valid format), and age (non-negative).

Expected output: Schema enforces data validation and uniqueness constraints.

Hint: Use required, unique, and match validators in the schema definition.

Add Indexes for Performance

Add indexes on the username and email fields in your user schema to improve query speed.

Expected output: Indexes are created and queries on username/email are faster.

Hint: Use schema.index() method or define indexes in the schema fields.

You should use connection pooling by creating a single shared connection instance during app startup and reuse it throughout the app lifecycle to avoid overhead and resource exhaustion.

Schema validation ensures data consistency and prevents invalid data from being stored, which is important because MongoDB itself is schema-less and does not enforce data structure.

Creating indexes on frequently queried fields, using projections to limit returned fields, avoiding large documents, and analyzing queries with explain() are key optimization techniques.