ZXC WebAssembly

High-performance lossless compression for the browser and Node.js via WebAssembly.

Features

• Buffer API: Compress and decompress Uint8Array buffers
• Reusable Contexts: Amortise allocation overhead across multiple operations
• All Levels: Compression levels 1–5
• Checksum Support: Optional integrity verification
• Tiny Footprint: ~60 KB .wasm file (scalar build, no SIMD)

Quick Start

Browser (ES Module)

import createZXC from './zxc_wasm.js';

const zxc = await createZXC();

// Compress
const input = new TextEncoder().encode('Hello, World!');
const compressed = zxc.compress(input, { level: 3 });

// Decompress
const output = zxc.decompress(compressed);
console.log(new TextDecoder().decode(output)); // "Hello, World!"

Node.js

import createZXC from 'zxc-wasm';
import { readFileSync } from 'fs';

const zxc = await createZXC();
const data = new Uint8Array(readFileSync('input.bin'));

const compressed = zxc.compress(data, { level: 5, checksum: true });
const decompressed = zxc.decompress(compressed, { checksum: true });

API Reference

createZXC(moduleOverrides?) → Promise<ZXC>

Initialise the WASM module. Returns a frozen API object.

zxc.compress(data, opts?) → Uint8Array

Option	Type	Default	Description
level	number	3	Compression level (1–5)
checksum	boolean	false	Enable integrity checksums

zxc.decompress(data, opts?) → Uint8Array

Option	Type	Default	Description
checksum	boolean	false	Verify integrity checksums

zxc.compressBound(inputSize) → number

Maximum compressed output size for a given input size.

zxc.getDecompressedSize(data) → number

Read the original size from a compressed buffer without decompressing.

zxc.createCompressContext(opts?) → CompressContext

Create a reusable compression context (avoids per-call allocation).

const ctx = zxc.createCompressContext({ level: 3 });
const c1 = ctx.compress(data1);
const c2 = ctx.compress(data2);
ctx.free(); // Release WASM memory

zxc.createDecompressContext() → DecompressContext

Create a reusable decompression context.

const ctx = zxc.createDecompressContext();
const d1 = ctx.decompress(compressed1);
const d2 = ctx.decompress(compressed2);
ctx.free();

Properties

Property	Type	Description
version	string	Library version (e.g. "0.10.0")
minLevel	number	Minimum compression level (1)
maxLevel	number	Maximum compression level (5)
defaultLevel	number	Default compression level (3)

Building from Source

Requires Emscripten SDK.

# Configure
emcmake cmake -B build-wasm -DCMAKE_BUILD_TYPE=Release

# Build
cmake --build build-wasm

# Test
BUILD_DIR=build-wasm node wrappers/wasm/test.mjs

The build produces build-wasm/zxc.js and build-wasm/zxc.wasm.

License

BSD 3-Clause. See LICENSE.