lzjs

lzjs is a JavaScript library that compresses and decompresses strings using an original algorithm based on the LZ algorithm.

This can be particularly useful when storing large amounts of data in storage with size limitations, such as localStorage or cookies.

Installation

npm

$ npm install --save lzjs

using import

import lzjs from 'lzjs';

using require

const lzjs = require('lzjs');

browser (standalone)

You can install the library via npm or download it from the release list. Use the lzjs.js or lzjs.min.js files included in the package.
*Please note that if you use git clone, even the master branch may be under development.

<script src="lzjs.js"></script>

or the minified lzjs.min.js:

<script src="lzjs.min.js"></script>

When the script is loaded, the lzjs object is defined in the global scope (i.e., window.lzjs).

Demo

• lzjs compression demo

API

• compress
• decompress
• compressToBase64
• decompressFromBase64

lzjs.compress(data, [options])

Compresses data into a binary string.

Arguments

• data (string|Buffer) : Input data
• [options] (object) : Compression options
  • onData (function (data) {}) : Called when a data is chunked
  • onEnd (function () {}) : Called when process ends

Returns

(string) : Compressed data

Example

Example of compressing and decompressing a string.

const data = 'hello hello hello';
const compressed = lzjs.compress(data);
console.log(compressed); // 'Whello \x80\x82\x84\x86\x83'

const decompressed = lzjs.decompress(compressed);
console.log(decompressed === data); // true

Compress data using onData and onEnd events.

const string = 'hello hello hello';
const compressed = [];

lzjs.compress(string, {
  onData: (data) => {
    compressed.push(data);
  },
  onEnd: () => {
    console.log(compressed.join('')); // 'Whello \x80\x82\x84\x86\x83'
  }
});

lzjs.decompress(data, [options])

Decompresses a string that has been compressed with lzjs.compress()

Arguments

• data (string) : Input data
• [options] (object) : Decompression options
  • onData (function (data) {}) : Called when a data is chunked
  • onEnd (function () {}) : Called when process ends

Returns

(string) : Decompressed data

Example

Example of decompressing a string that has been compressed with lzjs.compress().

const decompressed = lzjs.decompress('Wabc\x80\x82\x81\x83\x83');
console.log(decompressed); // 'abcabcabcabcabc'

Decompress data using onData and onEnd events.

const compressed = 'Whello \x80\x82\x84\x86\x83';
const decompressed = [];

lzjs.decompress(compressed, {
  onData: (data) => {
    decompressed.push(data);
  },
  onEnd: () => {
    console.log(decompressed.join('')); // 'hello hello hello'
  }
});

lzjs.compressToBase64(data)

Compresses and encodes data into a Base64 string.

Arguments

• data (string|Buffer) : Input data

Returns

(string) : Compressed and Base64 encoded string

Example

const data = 'hello hello hello';
const compressed = lzjs.compressToBase64(data);
console.log(compressed); // 'V2hlbGxvIMKAwoLChMKGwoM='

lzjs.decompressFromBase64(data)

Decompresses a string that has been compressed with lzjs.compressToBase64().

Arguments

• data (string) : Input data

Returns

(string) : Decompressed data

Example

const decompressed = lzjs.decompressFromBase64('V2FiY8KAwoLCgcKDwoM=');
console.log(decompressed); // 'abcabcabcabcabc'

Command line usage

After npm install -g lzjs

Add file to archive

lzjs -a something.txt

Extract file

lzjs -x something.txt.lzjs

All command line options

  -h, --help                 show Help
  -v, --version              show Version
  -a, --add <file_name>      Add file to archive
  -x, --extract <file_name>  eXtract file

Note that command line compression is only valid for the UTF-8 encoded file.

Contributing

We welcome contributions from everyone. For bug reports and feature requests, please create an issue on GitHub.

Pull Requests

Before submitting a pull request, please run $ npm run test to ensure there are no errors. We only accept pull requests that pass all tests.

License

This project is licensed under the terms of the MIT license. See the LICENSE file for details.