Node.js Streams
🌊 Node.js – Streams
Streams are objects in Node.js that allow reading or writing data in chunks, instead of loading the entire data into memory.
This is memory-efficient and suitable for large files.
Streams are event-based and work with EventEmitter.
✅ 1. Types of Streams
| Type | Description | Example |
|---|---|---|
| Readable | Stream you can read data from | fs.createReadStream() |
| Writable | Stream you can write data to | fs.createWriteStream() |
| Duplex | Both readable and writable | TCP sockets |
| Transform | Modify data while reading/writing | zlib.createGzip() |
✅ 2. Readable Streams
Used to read data in chunks.
✅ 3. Writable Streams
Used to write data in chunks.
✅ 4. Pipe Streams
You can pipe data from a readable stream to a writable stream easily.
✅ Automatically handles data events and writes data efficiently.
✅ 5. Transform Streams
Used to modify data while reading/writing.
Example: Convert text to uppercase.
✅ 6. Duplex Streams
Both readable and writable.
Example: TCP socket (simplified):
✅ 7. Event Listeners in Streams
| Event | Description |
|---|---|
data | Triggered when a chunk is available (Readable) |
end | Triggered when all data is read |
error | Triggered when an error occurs |
finish | Triggered when writing is complete (Writable) |
pipe | Triggered when piping starts |
unpipe | Triggered when piping stops |
✅ 8. Example: Read + Transform + Write Stream
🎯 Advantages of Streams
Efficient memory usage
Handle large files without crashing
Supports piping & chaining
Real-time processing of data
Works well with network operations
