URL Encoder / Decoder

// Component encoding — encodes individual values for query parameters
function encodeComponent(str) {
  return encodeURIComponent(str)
    .replace(/%20/g, '+')
    .replace(/!/g, '%21')
    .replace(/'/g, '%27')
    .replace(/\(/g, '%28')
    .replace(/\)/g, '%29')
    .replace(/\*/g, '%2A');
}

function decodeComponent(str) {
  return decodeURIComponent(str.replace(/\+/g, ' '));
}

// Full URL encoding — preserves URL structure
function encodeFullURL(url) {
  try {
    const parsed = new URL(url);
    if (parsed.search) {
      const params = new URLSearchParams(parsed.search);
      for (const [key, value] of params) {
        params.set(key, encodeComponent(value));
      }
      parsed.search = params.toString();
    }
    return parsed.toString();
  } catch {
    return encodeComponent(url);
  }
}

// Usage
const query = 'search=hello world & lang=zh';
console.log(encodeComponent('hello world & lang=zh'));
// hello+world+%26+lang%3Dzh

console.log(decodeComponent('hello+world+%26+lang%3Dzh'));
// hello world & lang=zh

function buildQueryString(params) {
  return Object.entries(params)
    .map(([key, value]) => {
      const encodedKey = encodeURIComponent(key);
      const encodedValue = encodeURIComponent(String(value))
        .replace(/%20/g, '+');
      return `${encodedKey}=${encodedValue}`;
    })
    .join('&');
}

// Usage
const searchParams = {
  q: 'machine learning & AI',
  lang: 'en',
  page: 1,
  sort: 'relevance desc'
};

const queryString = buildQueryString(searchParams);
console.log(queryString);
// q=machine+learning+%26+AI&lang=en&page=1&sort=relevance+desc

// Construct full URL
const url = `https://api.example.com/search?${queryString}`;
console.log(url);