UUID Tools

function parseUUID(uuidString) {
  // Remove URN prefix if present
  const clean = uuidString.replace(/^urn:uuid:/i, '').toLowerCase();

  // Validate format: 8-4-4-4-12 hex chars
  const match = clean.match(
    /^[0-9a-f]{8}-[0-9a-f]{4}-([0-9a-f]{4})-([0-9a-f]{4})-[0-9a-f]{12}$/
  );
  if (!match) throw new Error('Invalid UUID format');

  // Extract version (byte 6 high nibble)
  const versionHex = match[1][0];
  const version = parseInt(versionHex, 16);

  // Extract variant (byte 8 high bits)
  const variantHex = match[2][0];
  const variantBits = parseInt(variantHex, 16);
  let variant;
  if (variantBits >= 8 && variantBits <= 11) variant = 'RFC 4122';
  else if (variantBits >= 12 && variantBits <= 13) variant = 'Microsoft';
  else if (variantBits === 14) variant = 'Reserved';
  else variant = 'NCS';

  // Extract timestamp for v1 and v7
  let timestamp = null;
  if (version === 1) {
    const timeLow = parseInt(clean.slice(0, 8), 16);
    const timeMid = parseInt(clean.slice(9, 13), 16);
    const timeHi = parseInt(clean.slice(14, 18), 16) & 0x0fff;
    const time = (timeHi * 2**48) + (timeMid * 2**32) + timeLow;
    timestamp = new Date((time - 122192928000000000) / 10000);
  } else if (version === 7) {
    const timeHex = clean.slice(0, 12).replace(/-/g, '');
    const timeMs = parseInt(timeHex, 16);
    timestamp = new Date(timeMs);
  }

  return {
    uuid: uuidString,
    valid: true,
    version,
    variant,
    timestamp: timestamp ? timestamp.toISOString() : null,
    bytes: clean.replace(/-/g, '')
  };
}

// Usage
console.log(parseUUID('f47ac10b-58cc-4372-a567-0e02b2c3d479'));
// { version: 4, variant: 'RFC 4122', timestamp: null, ... }

function uuidToBinary(uuidString) {
  const hex = uuidString.replace(/-/g, '');
  return hex.match(/.{2}/g).map(b => parseInt(b, 16));
}

function binaryToUUID(bytes) {
  const hex = bytes.map(b => b.toString(16).padStart(2, '0')).join('');
  return [
    hex.slice(0, 8),
    hex.slice(8, 12),
    hex.slice(12, 16),
    hex.slice(16, 20),
    hex.slice(20)
  ].join('-');
}

function uuidToURN(uuidString) {
  return `urn:uuid:${uuidString.toLowerCase()}`;
}

// Usage
const uuid = '550e8400-e29b-41d4-a716-446655440000';
const binary = uuidToBinary(uuid);
const backToUUID = binaryToUUID(binary);
const urn = uuidToURN(uuid);

console.log(binary);  // [85, 14, 232, 64, ...]
console.log(backToUUID); // 550e8400-e29b-41d4-a716-446655440000
console.log(urn); // urn:uuid:550e8400-e29b-41d4-a716-446655440000