lzma1
v0.0.6
Published
A JavaScript implementation of the Lempel-Ziv-Markov (LZMA) chain compression algorithm
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Maintainers
xsemanReadme
lzma1
This is a fork of Nathan Rugg's LZMA-JS package.
Why
There are many LZMA implementations in JavaScript, but most are outdated,
unmaintained, lack type support, or rely on specific runtime APIs (e.g., Node.js
Buffer).
This version has been cleaned up, with TypeScript types added to make it easier to read and maintain.
Features
- Encode and decode LZMA streams
- Supports both string and Uint8Array data
- Supports both browser and Node.js environments
- Pure JavaScript implementation with TypeScript types
- No dependencies on runtime-specific APIs
Installation
[!NOTE] This package is native ESM and no longer provides a CommonJS export. If your project uses CommonJS, you will have to convert to ESM or use the dynamic
import()function.
npm
npm install lzma1browser
<script type="module">
import { compress, decompress } from "https://esm.sh/lzma1@latest";
</script>Quick start
The library provides two main functions: compress and decompress:
compress(data: string | Uint8Array, mode?: Mode): Int8Array
decompress(data: Uint8Array | ArrayBuffer): string | Int8ArrayCompressing a string
import {
compress,
decompress,
} from "lzma1";
const data = "Hello World!";
const compressed = compress(data, 1); // Using compression level 1 (fastest)
const decompressed = decompress(compressed);
// data === decompressedWorking with binary data
import {
compress,
decompress,
} from "lzma1";
// Compress binary data
const binaryData = new Uint8Array([0x01, 0x02, 0x03, 0x04]);
const compressed = compress(binaryData, 5); // Default compression level
// Decompress back to binary
const decompressed = decompress(compressed);
// decompressed will be an Int8ArrayHTML example
A simple browser example:
<!DOCTYPE html>
<html>
<body>
<textarea id="input">Hello World!</textarea><br>
<button id="run">Compress & Decompress</button>>
<div id="result"></div>
<script type="module">
import { compress, decompress } from "https://esm.sh/lzma1@latest";
document.getElementById("run").onclick = () => {
const text = document.getElementById("input").value;
const compressed = compress(text);
const decompressed = decompress(compressed);
document.getElementById("result").innerHTML =
`Original: ${text.length} bytes<br>` +
`Compressed: ${compressed.length} bytes<br>` +
`Result: ${decompressed}`;
};
</script>
</body>
</html>Advanced usage
You can control the compression level (1-9) to balance between speed and compression ratio:
import { compress } from "lzma1";
// Fastest compression (level 1)
const fastCompressed = compress(data, 1);
// Balanced compression (level 5)
const balancedCompressed = compress(data, 5);
// Maximum compression (level 9)
const maxCompressed = compress(data, 9);How it works
LZMA (Lempel-Ziv-Markov chain Algorithm) is a compression algorithm that uses a dictionary compression scheme. It's known for its high compression ratio and is commonly used in the 7z archive format.
LZMA header
The LZMA compressed data begins with a header that contains information needed for decompression:
More information about the LZMA header structure.