LZ JavaScript compression

LZ compression for JavaScript compresses and decompresses JavaScript strings.

Features

• Easy to use.
• Fast LZipperLite.js is faster than any LZW JavaScript compression I have tested so far.

Status

First release for ECMAScript6 Added LZipperLite that is compatible with ECMAScript5 Removed older versions now only using LZipperLite

Including it in you project

Simply add LZipperLite.js

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

API

LZipperLite.js adds the global object LZipper to the global name-space providing four functions

String = LZipper.compress(String);
String = LZipper.decompress(String)
String = LZipper.char2Int(String)
String = LZipper.int2Char(String)

Methods.

LZipper.compress Arguments data a String to be compressed. returns a string representing a compressed version of the input string

LZipper.decompress Arguments compressed a compressed string. returns an uncompressed string.

LZipper.int2Char Arguments String a javascript 16 bit unicode string returns String 8 bit encoded unicode string. Uses only the first 8bits to encode all the unicode characters so that the string can be converted to Base64 via window.btoa

LZipper.int2Char Arguments String a javascript 8 bit encoded 16bit unicode string. See above returns String The 16 bit unicode string

Usage example

LZipper is handy for storing data in localStorage

Save to local storage.

// myObject represents a javascript object.
localStorage.myData = LZipper.compress ( JSON.stringify (myObject) ); // save compress JSON to local storage

Retrieval.

var myObject;
if (localStorage.myData !== undefined) {
    myObject = JSON.parse ( LZipper.decompress ( localStorage.myData ));
}

I have added two functions to allow the compressed string to be converted to Base64 so it can be added to a URL, this is to deal with the URL size limitations that browsers have.

To compress and add to a URL

var data = JSON.stringify(myData);
var href = "http://myweb.com/page.html?data=" + btoa(LZipper.int2Char(LZipper.compress(data)))

To decompress from url

var data = location.href.split("?data=")[0];
var myData = JSON.parse(LZipper.decompress(LZipper.char2Int(atob(data))));

Current limitations.

Knowledge of JavaScript