Generatorbasierte Zustandsbehaftete Token-Bucket-Ratenbegrenzung für Next.js-Middleware

export function* createTokenBucket(capacity, refillRatePerSec) {
  let tokens = capacity;
  let lastRefill = Date.now();
 
  while (true) {
    const now = Date.now();
    const elapsedSeconds = (now - lastRefill) / 1000;
    tokens = Math.min(capacity, tokens + elapsedSeconds * refillRatePerSec);
    lastRefill = now;
 
    const requested = yield { allowed: tokens >= 1, remaining: Math.floor(tokens) };
    if (requested && tokens >= requested) {
      tokens -= requested;
    }
  }
}