function uint8ArrayToBase64(uint8Array: Uint8Array) {
  return btoa(
    Array.from(uint8Array)
      .map((byte) => String.fromCharCode(byte))
      .join("")
  );
}

fetch(
  "https://cf-assets.www.cloudflare.com/slt3lc6tev37/6ZH2Etm3LlFHTgmkjLmkxp/59ff240fb3ebdc7794ffaa6e1d69b7c2/osi_model_7_layers.png"
)
  .then((response) => response.bytes())
  .then((bytes) => {
    console.log(bytes);
    console.log(uint8ArrayToBase64(bytes));
  });