compress

Compression and encoding utilities for data compression, decompression, and various encoding formats including gzip, deflate, LZW, base64, URL, and HTML encoding.

Functions

Function	Description	Example
gzip	Compress with gzip	await dphelper.compress.gzip('Hello World')
gunzip	Decompress gzip	await dphelper.compress.gunzip(compressedBlob)
deflate	Compress with deflate	await dphelper.compress.deflate('Hello World')
inflate	Decompress deflate	await dphelper.compress.inflate(compressedBlob)
compress	LZW compress	dphelper.compress.compress('Hello World')
decompress	LZW decompress	dphelper.compress.decompress(compressedString)
base64Encode	Encode to base64	dphelper.compress.base64Encode('Hello')
base64Decode	Decode from base64	dphelper.compress.base64Decode('SGVsbG8=')
urlEncode	URL encode	dphelper.compress.urlEncode('Hello World!')
urlDecode	URL decode	dphelper.compress.urlDecode('Hello%20World!')
htmlEncode	HTML encode	dphelper.compress.htmlEncode('<script>')
htmlDecode	HTML decode	dphelper.compress.htmlDecode('<script>')

Description

Comprehensive compression and encoding module providing:

• Gzip/Deflate - Browser-native compression using CompressionStream API

• LZW Compression - JavaScript-compatible compression for data storage

• Base64 - Binary-to-text encoding for data transfer

• URL Encoding - Percent-encoding for URLs and query strings

• HTML Encoding - Escape special characters for safe HTML rendering

• Universal - Works in both browser and server environments

Usage Examples

Gzip Compression

// Compress string with gzip
const original = 'Hello World! This is a test string for compression.';
const compressed = await dphelper.compress.gzip(original);

console.log('Original size:', original.length);
console.log('Compressed type:', compressed.type); // "application/gzip"

// Decompress
const decompressed = await dphelper.compress.gunzip(compressed);
console.log('Decompressed:', decompressed); // "Hello World! This is a test..."

Deflate Compression

// Compress with deflate (smaller than gzip, no header)
const data = JSON.stringify({ users: [...], metadata: {...} });
const deflated = await dphelper.compress.deflate(data);

// Decompress
const inflated = await dphelper.compress.inflate(deflated);
console.log(JSON.parse(inflated));

LZW Compression (JavaScript Compatible)

// LZW compression - works in both browser and Node.js
const original = 'ABABABABABABABAB';
const compressed = dphelper.compress.compress(original);

console.log('Original:', original.length, 'chars');
console.log('Compressed:', compressed.length, 'chars');

// Decompress
const decompressed = dphelper.compress.decompress(compressed);
console.log('Decompressed:', decompressed); // "ABABABABABABABAB"

Base64 Encoding

// Encode string to base64
const plain = 'Hello, World!';
const encoded = dphelper.compress.base64Encode(plain);
console.log(encoded); // "SGVsbG8sIFdvcmxkIQ=="

// Decode from base64
const decoded = dphelper.compress.base64Decode(encoded);
console.log(decoded); // "Hello, World!"

// Encode binary data
const bytes = new Uint8Array([72, 101, 108, 108, 111]);
const binaryEncoded = dphelper.compress.base64Encode(String.fromCharCode(...bytes));
console.log(binaryEncoded); // "SGVsbG8="

URL Encoding

// URL encode (percent-encoding)
const url = 'Hello World! Test=1&value=abc';
const encoded = dphelper.compress.urlEncode(url);
console.log(encoded); // "Hello%20World!%20Test%3D1%26value%3Dabc"

// URL decode
const decoded = dphelper.compress.urlDecode(encoded);
console.log(decoded); // "Hello World! Test=1&value=abc"

// Encode for query string
const query = 'name=John Doe&city=New York';
const queryEncoded = dphelper.compress.urlEncode(query);
console.log(queryEncoded); // "name%3DJohn%20Doe%26city%3DNew%20York"

HTML Encoding

// HTML encode (escape special characters)
const unsafe = '<script>alert("XSS!")</script>';
const encoded = dphelper.compress.htmlEncode(unsafe);
console.log(encoded);
// "<script>alert("XSS!")</script>"

// HTML decode
const decoded = dphelper.compress.htmlDecode(encoded);
console.log(decoded); // '<script>alert("XSS!")</script>'

// Encode user input before displaying
const userInput = '<div onclick="evil()">Click me</div>';
const safe = dphelper.compress.htmlEncode(userInput);
// In HTML: <div onclick="evil()">Click me</div>

Advanced Usage

Data Compression for Storage

class CompressedStorage {
  async compress(key, data) {
    const json = JSON.stringify(data);
    const compressed = await dphelper.compress.gzip(json);
    localStorage.setItem(key, await compressed.text());
  }

  async decompress(key) {
    const stored = localStorage.getItem(key);
    if (!stored) return null;

    const blob = new Blob([stored], { type: 'application/gzip' });
    const decompressed = await dphelper.compress.gunzip(blob);
    return JSON.parse(decompressed);
  }
}

// Usage
const storage = new CompressedStorage();
await storage.compress('cache', { users: [...], timestamp: Date.now() });
const data = await storage.decompress('cache');

API Response Compression

// Compress data before sending to server
async function sendCompressed(url, data) {
  const json = JSON.stringify(data);
  const compressed = await dphelper.compress.gzip(json);

  return fetch(url, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/gzip'
    },
    body: compressed
  });
}

// Decompress server response
async function fetchCompressed(url) {
  const response = await fetch(url);
  const compressed = await response.blob();
  const decompressed = await dphelper.compress.gunzip(compressed);
  return JSON.parse(decompressed);
}

String Compression for URLs

// Compress data for URL-safe storage (using LZW)
function compressForUrl(data) {
  const compressed = dphelper.compress.compress(JSON.stringify(data));
  return dphelper.compress.base64Encode(compressed)
    .replace(/\+/g, '-')
    .replace(/\//g, '_')
    .replace(/=+$/, '');
}

// Decompress from URL
function decompressFromUrl(encoded) {
  const base64 = encoded.replace(/-/g, '+').replace(/_/g, '/');
  const padded = base64.padEnd(base64.length + (4 - base64.length % 4) % 4, '=');
  const compressed = dphelper.compress.base64Decode(padded);
  return JSON.parse(dphelper.compress.decompress(compressed));
}

// Usage
const data = { id: 123, type: 'test', values: [1,2,3] };
const encoded = compressForUrl(data);
console.log(encoded); // URL-safe compressed string

const decoded = decompressFromUrl(encoded);
console.log(decoded); // { id: 123, type: 'test', values: [1,2,3] }

Secure Data Transfer

// Encode sensitive data for transfer
function encodeSecure(data) {
  const json = JSON.stringify(data);
  const base64 = dphelper.compress.base64Encode(json);
  return base64;
}

// Decode secure data
function decodeSecure(encoded) {
  const json = dphelper.compress.base64Decode(encoded);
  return JSON.parse(json);
}

// Sanitize HTML content
function sanitizeHtml(content) {
  return dphelper.compress.htmlEncode(content);
}

// Build safe query string
function buildQueryString(params) {
  return Object.entries(params)
    .map(([k, v]) => `${dphelper.compress.urlEncode(k)}=${dphelper.compress.urlEncode(v)}`)
    .join('&');
}

console.log(buildQueryString({ name: 'John Doe', age: '30' }));
// "name=John%20Doe=30"

Cache with Compression

class CacheManager {
  constructor(prefix = 'cache_') {
    this.prefix = prefix;
  }

  async set(key, value, maxAge = 3600000) {
    const entry = {
      data: value,
      expires: Date.now() + maxAge
    };

    const compressed = await dphelper.compress.gzip(JSON.stringify(entry));
    localStorage.setItem(
      this.prefix + key,
      await compressed.text()
    );
  }

  async get(key) {
    const stored = localStorage.getItem(this.prefix + key);
    if (!stored) return null;

    try {
      const blob = new Blob([stored], { type: 'application/gzip' });
      const decompressed = await dphelper.compress.gunzip(blob);
      const entry = JSON.parse(decompressed);

      if (Date.now() > entry.expires) {
        localStorage.removeItem(this.prefix + key);
        return null;
      }

      return entry.data;
    } catch {
      return null;
    }
  }

  clear() {
    Object.keys(localStorage)
      .filter(k => k.startsWith(this.prefix))
      .forEach(k => localStorage.removeItem(k));
  }
}

// Usage
const cache = new CacheManager();
await cache.set('user_123', { name: 'John', email: '[e-mail]' });
const user = await cache.get('user_123');

Details

• Author: Dario Passariello

• Version: 0.0.1

• Creation Date: 20260313

• Last Modified: 20260313

• Environment: Works in both client and server environments

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