@tokenizer/inflate

@tokenizer/inflate is a package designed for handling and extracting data from ZIP files efficiently using a tokenizer-based approach. The library provides a customizable way to parse ZIP archives and extract compressed data while minimizing memory usage.

Features

• Efficient Decompression: Handles streams compressed with DEFLATE and related formats (e.g., gzip).
• Tokenizer Compatibility: Seamlessly integrates with strtok3. For example, use @tokenizer/s3 for efficient partial extraction of a Zip stored on AWS S3 cloud file storage.
• Streamlined Interface: Provides an intuitive API for working with compressed data in streaming and random-access scenarios.
• Chunked Data Access: Leverages the underlying media's capabilities to offer chunked or random access to data, unlike traditional streams.
• Plug-and-Play: Easily integrate with existing tokenizer-based workflows for parsing file metadata or binary structures.
• Interrupt the extraction process conditionally.

Installation

npm install @tokenizer/inflate

Usage

Example: Extracting Specific Files

The following example demonstrates how to use the library to extract .txt files and stop processing when encountering a .stop file.

import { ZipHandler } from '@tokenizer/inflate';
import { fromFile } from 'strtok3';

const fileFilter = (file) => {
  console.log(`Processing file: ${file.filename}`);

  if (file.filename?.endsWith(".stop")) {
    console.log(`Stopping processing due to file: ${file.filename}`);
    return { handler: false, stop: true }; // Stop the unzip process
  }

  if (file.filename?.endsWith(".txt")) {
    return {
      handler: async (data) => {
        console.log(`Extracted text file: ${file.filename}`);
        console.log(new TextDecoder().decode(data));
      },
    };
  }

  return { handler: false }; // Ignore other files
};

async function extractFiles(zipFilePath) {
  const tokenizer = await fromFile(zipFilePath);
  const zipHandler = new ZipHandler(tokenizer);
  await zipHandler.unzip(fileFilter);
}

extractFiles('example.zip').catch(console.error);

API

ZipHandler

A class for handling ZIP file parsing and extraction.

Constructor

new ZipHandler(tokenizer: ITokenizer)

• tokenizer: An instance of ITokenizer to read the ZIP archive.

Methods

• isZip(): Promise<boolean>

  Determines whether the input file is a ZIP archive.

• unzip(fileCb: InflateFileFilter): Promise<void>

  Extracts files from the ZIP archive, applying the provided InflateFileFilter callback to each file.

InflatedDataHandler

Types

InflateFileFilter

type InflateFileFilter = (file: IFullZipHeader) => InflateFileFilterResult;

Callback function to determine whether a file should be handled or ignored.

InflateFileFilterResult

type InflateFileFilterResult = {
  handler: InflatedDataHandler | false; // Handle file data or ignore
  stop?: boolean; // Stop processing further files
};

Returned from InflateFileFilter to control file handling and extraction flow.

InflatedDataHandler

type InflatedDataHandler = (fileData: Uint8Array) => Promise<void>;

Handler for processing uncompressed file data.

Compatibility

Starting with version 7, the module has migrated from CommonJS to pure ECMAScript Module (ESM). The distributed JavaScript codebase is compliant with the ECMAScript 2020 (11th Edition) standard.

License

This project is licensed under the MIT License. See the LICENSE file for details.