Questions

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1How do you read a file synchronously in Node.js?

2How do you read a file asynchronously in Node.js?

3Explain how to write to a file in Node.js?

4What is the purpose of the `fs.exists()` method in Node.js?

5How can you delete a file in Node.js?

6What is the purpose of the `fs.createReadStream()` and `fs.createWriteStream()` methods in Node.js?

7How can you check if a given path is a file or a directory in Node.js?

8Explain the difference between `fs.readFile()` and `fs.createReadStream()` for reading files in Node.js.

9How can you append data to an existing file in Node.js?

10How can you recursively list all files and directories in a given directory using Node.js?

11What is the purpose of the `fs.mkdir()` method in Node.js, and how can you create directories with it?

12How can you rename a file or directory in Node.js?

13Explain what the `fs.readdir()` method is used for in Node.js.

14What is the purpose of the `fs.rmdir()` method in Node.js, and how can you delete a directory with it?

15What is the difference between `fs.unlink()` and `fs.unlinkSync()` in Node.js?

16How can you watch for file changes in a directory using Node.js?

nodejs

File Operations

Performance Optimisation

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How can you rename a file or directory in Node.js?

You can rename a file or directory in Node.js using the fs.rename() method. Here's an example:

javascript

Difficulty: 5/10

Topics: fs.rename, error handling, cross-platform considerations

Scenario Questions

0-2 years experience

1
We need to move an uploaded image into a 'processed' folder and rename it to include a timestamp. How would you implement that in Node.js?
2
What happens if you try to rename a file to a name that already exists on the same filesystem, and how would you handle that situation?
3
Show me a short snippet that renames a directory synchronously. When might you choose the sync version over the async one?

2-5 years experience

1
Our batch job sometimes throws an EXDEV error when renaming files. Why does this occur and how would you resolve it?
2
We need to rename files that may reside on different mounted volumes. Discuss the trade‑offs between using fs.rename versus copying then deleting.
3
A deployment script that renames configuration files is failing silently. How would you add robust error handling and logging?

5-8 years experience

1
Design a microservice that handles thousands of rename requests per second, guarantees atomicity, and avoids race conditions when two requests target the same path. Which Node.js APIs and architectural patterns would you choose?
2
Explain how you would implement a retry mechanism for rename operations that can fail due to temporary file locks while keeping throughput high.
3
What are the implications of using fs.rename on a network file system in a distributed environment, and how would you ensure consistency?

8+ years experience

1
Our legacy codebase uses callback‑based fs.rename throughout many services. We want to migrate to a promise/async‑await utility without breaking existing workflows. What migration strategy would you propose?
2
We are launching a cross‑team initiative to standardize file‑management APIs, including rename, across all Node.js services. How would you design an abstraction layer, version it, and manage the rollout while minimizing operational risk?
3
In a multi‑tenant SaaS platform, renames must satisfy strict audit, rollback, and compliance requirements. How would you architect the rename feature to meet these constraints across teams?

Follow-up Questions

❓What edge cases would you add unit tests for?
❓How would you surface rename failures to an operations dashboard?
❓Can you compare the callback API with the promise‑based version?