A stream is an abstract interface for working with streaming data in Node.js. The stream module provides a base API that makes it easy to build objects that implement the stream interface.
There are many stream objects provided by Node.js. For instance, a request to an HTTP server and process.stdout are both stream instances.
Streams can be readable, writable, or both. All streams are instances of EventEmitter.
The stream module can be accessed using:
const stream = require('stream');
There are four fundamental stream types within Node.js:
- Readable - streams from which data can be read (for example fs.createReadStream()).
- Writable - streams to which data can be written (for example fs.createWriteStream()).
- Duplex - streams that are both Readable and Writable (for example net.Socket).
- Transform - Duplex streams that can modify or transform the data as it is written and read (for example zlib.createDeflate()).
