How to read records in MongoDB via Node.js?

0-2 years experience

1. 1We have a Node.js service that needs to fetch all users older than 30 from a MongoDB collection. How would you write the code to perform this query and return the results?
2. 2If the query returns no documents, what does the Node.js driver return, and how would you handle that case in your code?

2-5 years experience

1. 1Our API endpoint returns a paginated list of orders. Explain how you would implement pagination using MongoDB cursors in Node.js, and what trade‑offs exist between skip/limit and range‑based pagination.
2. 2During a recent deployment, the read operation started timing out intermittently. Walk me through how you would debug the issue, considering connection pool settings and read preferences.

5-8 years experience

1. 1We need to serve high‑traffic read‑heavy workloads from a sharded MongoDB cluster. How would you design the Node.js data access layer to minimize latency and ensure consistent reads across shards?
2. 2Describe how you would implement a resilient read strategy that falls back to secondary replicas when the primary is overloaded, and what impact this has on data consistency.

8+ years experience

1. 1Our organization is migrating from a monolithic Node.js app to a microservices architecture, each service reading from shared MongoDB collections. What architectural guidelines would you establish for read patterns, schema versioning, and cross‑service data contracts to avoid coupling and ensure scalability?
2. 2If we plan to introduce a read‑through cache (e.g., Redis) in front of MongoDB, how would you decide which queries to cache, handle cache invalidation, and measure the performance benefits at a system level?