unzipper

What is unzipper?

The unzipper npm package is a module that provides streaming APIs for unzipping .zip files. It allows for extracting the contents of zip files, parsing zip file structures, and more, all while being memory efficient and fast.

What are unzipper's main functionalities?

Extracting zip files

This feature allows you to extract the contents of a zip file to a specified directory. The code sample demonstrates how to read a zip file as a stream and pipe it to the unzipper's Extract method, which will extract the files to the given path.

const unzipper = require('unzipper');
const fs = require('fs');

fs.createReadStream('path/to/archive.zip')
  .pipe(unzipper.Extract({ path: 'output/path' }));

Parsing zip file entries

This feature allows you to parse the contents of a zip file and work with each entry individually. The code sample shows how to read entries from a zip file and handle them based on their type, either extracting files or draining directories.

const unzipper = require('unzipper');

fs.createReadStream('path/to/archive.zip')
  .pipe(unzipper.Parse())
  .on('entry', function (entry) {
    const fileName = entry.path;
    const type = entry.type; // 'Directory' or 'File'
    if (type === 'File') {
      entry.pipe(fs.createWriteStream('output/path/' + fileName));
    } else {
      entry.autodrain();
    }
  });

Buffer-based extraction

This feature allows you to extract files from a zip file that is already loaded into a buffer. The code sample demonstrates how to open a zip file from a buffer and then extract the contents of the first file into another buffer.

const unzipper = require('unzipper');

unzipper.Open.buffer(buffer)
  .then(function (directory) {
    return directory.files[0].buffer();
  })
  .then(function (contentBuffer) {
    // Use the contentBuffer
  });

Other packages similar to unzipper

adm-zip

adm-zip is a JavaScript implementation for zip data compression for NodeJS. It provides functionalities similar to unzipper, such as reading and extracting zip files. Unlike unzipper, which is stream-based, adm-zip works with in-memory buffers, which can be less efficient for large files.

jszip

jszip is a library for creating, reading, and editing .zip files with JavaScript, with a focus on client-side use. It can be used in NodeJS as well. It offers a more comprehensive API for handling zip files compared to unzipper, including the ability to generate zip files, but it might not be as optimized for streaming large zip files.

yauzl

yauzl is another NodeJS library for reading zip files. It focuses on low-level zip file parsing and decompression, providing a minimal API. It's designed to be more memory efficient than adm-zip by using lazy parsing, but it doesn't provide the high-level convenience methods that unzipper does.

README

unzipper

This is a fork of node-unzip which has not been maintained in a while. This fork addresses the following issues:

• finish/close events are not always triggered, particular when the input stream is slower than the receivers
• Any files are buffered into memory before passing on to entry

The stucture of this fork is identical to the original, but uses ES6, Promises and inherit guarantees provided by node streams to ensure low memory footprint and guarantee finish/close events at the end of processing.

Unzipper provides simple APIs similar to node-tar for parsing and extracting zip files. There are no added compiled dependencies - inflation is handled by node.js's built in zlib support.

Installation

$ npm install unzipper

Quick Examples

Extract to a directory

fs.createReadStream('path/to/archive.zip')
  .pipe(unzipper.Extract({ path: 'output/path' }));

Extract emits the 'close' event once the zip's contents have been fully extracted to disk.

Parse zip file contents

Process each zip file entry or pipe entries to another stream.

Important: If you do not intend to consume an entry stream's raw data, call autodrain() to dispose of the entry's contents. Otherwise you risk running out of memory.

fs.createReadStream('path/to/archive.zip')
  .pipe(unzipper.Parse())
  .on('entry', function (entry) {
    var fileName = entry.path;
    var type = entry.type; // 'Directory' or 'File'
    var size = entry.size;
    if (fileName === "this IS the file I'm looking for") {
      entry.pipe(fs.createWriteStream('output/path'));
    } else {
      entry.autodrain();
    }
  });

Or pipe the output of unzipper.Parse() to fstream

var readStream = fs.createReadStream('path/to/archive.zip');
var writeStream = fstream.Writer('output/path');

readStream
  .pipe(unzipper.Parse())
  .pipe(writeStream)

Licenses

See LICENCE