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

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

`fs.readFile()` reads the entire file into memory and then invokes the callback with the file's contents. It's suitable for small files but can be memory-intensive for large files. `fs.createReadStream()` reads the file in smaller chunks (buffers) and allows for streaming the file's contents. It's more memory-efficient and suitable for handling large files.

Difficulty: 3/10

file I/O, streaming, memory usage

1
fs.readFile() reads the entire file into memory and then invokes the callback with the file's contents. It's suitable for small files but can be memory-intensive for large files.
2
fs.createReadStream() reads the file in smaller chunks (buffers) and allows for streaming the file's contents. It's more memory-efficient and suitable for handling large files.

Scenario Questions

0-2 years experience

2-5 years experience

1A new feature processes user‑uploaded CSV files. It works for files under 1 MB but crashes on larger ones. How would you debug the problem and decide between readFile and createReadStream?

Follow-up Questions