Installation access tokens have expiration times (typically 1 hour) and should not be cached indefinitely. The current implementation caches InstallationAccessTokenAuthentication objects without considering token expiration, which could lead to using expired tokens.

Consider either:

1. Not caching installation auth objects at all, or
2. Implementing TTL-based caching that respects the token's expiresAt field from the authentication object

@copilot Lambda max TTL is 15 minutes

Storing tokens directly in cache keys is a security concern as it could expose sensitive credentials in memory dumps or logs. The full token value should not be part of the cache key.

Consider using a hash of the token instead:

import { createHash } from 'crypto';

export function createTokenCacheKey(token: string, ghesApiUrl: string = '') {
  const tokenHash = createHash('sha256').update(token).digest('hex').substring(0, 16);
  return `octokit-${tokenHash}-${ghesApiUrl}`;
}

The installationId field is defined in the GithubAppConfig interface but is never populated or used. It should either be:

1. Removed from the interface if not needed, or
2. Populated in the createAuth function (line 109-112) if it's intended to be part of the config

Currently, the installationId is handled separately in createAuth (line 119) rather than being part of the cached config.

The cache functions and key generation functions lack JSDoc documentation. Adding documentation would help other developers understand:

• The caching strategy and behavior
• When cached values are returned vs when the creator function is called
• The cache key format and what parameters affect it
• The purpose of the reset() function

Example:

/**
 * Creates a cache key for Octokit clients based on token and API URL.
 * @param token - The authentication token
 * @param ghesApiUrl - Optional GitHub Enterprise Server API URL
 * @returns A unique cache key for this token/URL combination
 */
export function createTokenCacheKey(token: string, ghesApiUrl: string = '') {
  return `octokit-${token}-${ghesApiUrl}`;
}

The cache key generation uses installationId || 'none' which treats falsy values (0, null, undefined) the same way. While 0 is likely not a valid GitHub installation ID, this could lead to cache key collisions for different falsy values.

Consider using nullish coalescing instead for more precise handling:

const id = installationId ?? 'none';

This will only treat null and undefined as 'none', while preserving 0 if it were ever a valid value.

String argument /[\\n]/g looks like a regular expression, but it will be interpreted as a string.