// WebAuthn speaks ArrayBuffers; everything crossing the wire is base64url.

/** @param {ArrayBuffer} buffer @returns {string} */
export function b64(buffer) {
  return btoa(String.fromCharCode(...new Uint8Array(buffer)))
    .replace(/\+/g, '-')
    .replace(/\//g, '_')
    .replace(/=+$/, '');
}

/** @param {string} value @returns {Uint8Array} */
export function unb64(value) {
  return Uint8Array.from(
    atob(value.replace(/-/g, '+').replace(/_/g, '/')),
    (character) => character.charCodeAt(0),
  );
}