armarius-io

About

This module contains implementations for reading from and writing to files, as well as implementations for deflate compression using various JavaScript APIs. It is mainly used by the armarius module.

Contained are IO contexts for Blob object (read only), ArrayBuffers, and Node.js FileHandle objects. Compression contexts exist for the CompressionStreams API, the Node.js zlib module, and the fflate library.

Installation

Armarius-IO can be installed using npm:

npm install armarius-io

Usage

IO contexts

IO contexts are objects that extend the IO class and can be used to read from or write to an underlying file or buffer. This library contains the following IO contexts:

• ArrayBufferIO - for reading from and writing to an ArrayBuffer
• BlobIO - for reading from a Blob or JavaScript File object
• NodeFileIO - for reading from and writing to a Node.js FileHandle object

ArrayBufferIO

let data = new Uint8Array(123);
let io = new ArrayBufferIO(data.buffer, data.byteOffset, data.byteLength);

BlobIO

let file = input.files[0];
let io = new BlobIO(file);

NodeFileIO

let file = await fs.promises.open('file.txt', 'r+');
let stat = await file.stat();
let io = new NodeFileIO(file, 0, stat.size);

DataStreams

DataStream objects can be used to read data from a source. All IO contexts also implement DataStream.

DataProcessors

DataProcessor objects read and transform data from a DataStream. This library includes DataProcessors for deflate compression using various JavaScript APIs.

• NativeDeflateDataProcessor and NativeInflateDataProcessor - for using the CompressionStreams API
• NodeDeflateDataProcessor and NodeInflateDataProcessor - for using the Node.js zlib module
• FflateDeflateDataProcessor and FflateInflateDataProcessor - for using the fflate library
• DefaultDeflateDataProcessor and DefaultInflateDataProcessor - for using the best available compression method