Base64 UUID generator using UUID version 4 and variant 2. URL friendly. Faster direct generation from random.

base64UUID.js

function generateBase64UUID() {
  const byteArray = new Uint8Array(16);
  window.crypto.getRandomValues(byteArray);

  // Set the UUID version (4) and variant (2)
  byteArray[6] = (byteArray[6] & 0x0f) | 0x40;
  byteArray[8] = (byteArray[8] & 0x3f) | 0x80;

  let base64String = '';
  const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_';

  for (let i = 0; i < 15;) {
    const byte1 = byteArray[i++];
    const byte2 = byteArray[i++];
    const byte3 = byteArray[i++];

    const base64Index1 = byte1 >> 2;
    const base64Index2 = ((byte1 & 0x03) << 4) | (byte2 >> 4);
    const base64Index3 = ((byte2 & 0x0F) << 2) | (byte3 >> 6);
    const base64Index4 = byte3 & 0x3F;

    base64String += characters[base64Index1] + characters[base64Index2] +
                    characters[base64Index3] + characters[base64Index4];
  }

  return base64String;
}

// const base64Uuid = generateBase64UUID();
// console.log('Base64 UUID:', base64Uuid);