fs-minipass

What is fs-minipass?

The fs-minipass npm package is a minimalistic implementation of a readable and writable stream for file system operations. It is designed to be lightweight and efficient, making it suitable for scenarios where you need to handle file streams with minimal overhead.

What are fs-minipass's main functionalities?

Reading from a file

This feature allows you to read data from a file using a Minipass stream. The code demonstrates how to create a readable stream from a file and pipe it through a Minipass instance to handle the data chunks.

const fs = require('fs');
const Minipass = require('fs-minipass');

const mp = new Minipass();
const readStream = fs.createReadStream('example.txt');

readStream.pipe(mp).on('data', (chunk) => {
  console.log('Read chunk:', chunk.toString());
});

Writing to a file

This feature allows you to write data to a file using a Minipass stream. The code demonstrates how to create a writable stream to a file and pipe data through a Minipass instance to write to the file.

const fs = require('fs');
const Minipass = require('fs-minipass');

const mp = new Minipass();
const writeStream = fs.createWriteStream('output.txt');

mp.pipe(writeStream);
mp.write('Hello, world!');
mp.end();

Transforming data

This feature allows you to transform data as it passes through a Minipass stream. The code demonstrates how to create a custom transform stream that converts data to uppercase before passing it along.

const Minipass = require('fs-minipass');

class UpperCaseTransform extends Minipass {
  write(chunk) {
    super.write(chunk.toString().toUpperCase());
  }
}

const mp = new UpperCaseTransform();
mp.on('data', (chunk) => {
  console.log('Transformed chunk:', chunk.toString());
});

mp.write('hello');
mp.write('world');
mp.end();

Other packages similar to fs-minipass

through2

The through2 package is a tiny wrapper around Node.js streams2 Transform to avoid explicit subclassing noise. It provides a simple API for creating transform streams, making it easy to handle data transformations. Compared to fs-minipass, through2 is more focused on providing a straightforward way to create transform streams, while fs-minipass offers a more minimalistic and lightweight approach.

readable-stream

The readable-stream package is a robust, feature-complete implementation of the Node.js streams API. It is designed to be a drop-in replacement for the built-in stream module, providing consistent behavior across different Node.js versions. Compared to fs-minipass, readable-stream is more comprehensive and feature-rich, but also comes with more overhead.

stream

The stream package is the Node.js core stream module, which provides a comprehensive API for working with streams. It includes support for readable, writable, duplex, and transform streams. Compared to fs-minipass, the core stream module is more feature-rich and versatile, but fs-minipass offers a more lightweight and minimalistic alternative for specific use cases.

README

fs-minipass

Filesystem streams based on minipass.

4 classes are exported:

• ReadStream
• ReadStreamSync
• WriteStream
• WriteStreamSync

When using ReadStreamSync, all of the data is made available immediately upon consuming the stream. Nothing is buffered in memory when the stream is constructed. If the stream is piped to a writer, then it will synchronously read() and emit data into the writer as fast as the writer can consume it. (That is, it will respect backpressure.) If you call stream.read() then it will read the entire file and return the contents.

When using WriteStreamSync, every write is flushed to the file synchronously. If your writes all come in a single tick, then it'll write it all out in a single tick. It's as synchronous as you are.

The async versions work much like their node builtin counterparts, with the exception of introducing significantly less Stream machinery overhead.

USAGE

It's just streams, you pipe them or read() them or write() to them.

const fsm = require('fs-minipass')
const readStream = new fsm.ReadStream('file.txt')
const writeStream = new fsm.WriteStream('output.txt')
writeStream.write('some file header or whatever\n')
readStream.pipe(writeStream)

ReadStream(path, options)

Path string is required, but somewhat irrelevant if an open file descriptor is passed in as an option.

Options:

• fd Pass in a numeric file descriptor, if the file is already open.
• readSize The size of reads to do, defaults to 16MB
• size The size of the file, if known. Prevents zero-byte read() call at the end.
• autoClose Set to false to prevent the file descriptor from being closed when the file is done being read.

WriteStream(path, options)

Path string is required, but somewhat irrelevant if an open file descriptor is passed in as an option.

Options:

• fd Pass in a numeric file descriptor, if the file is already open.
• mode The mode to create the file with. Defaults to 0o666.
• start The position in the file to start reading. If not specified, then the file will start writing at position zero, and be truncated by default.
• autoClose Set to false to prevent the file descriptor from being closed when the stream is ended.
• flags Flags to use when opening the file. Irrelevant if fd is passed in, since file won't be opened in that case. Defaults to 'a' if a pos is specified, or 'w' otherwise.