Momento/memento-note/lib/rate-limit.ts

const attempts = new Map<string, { count: number; resetAt: number }>()

const WINDOW_MS = 60_000
const MAX_ATTEMPTS = 5

export function rateLimit(key: string): { allowed: boolean; retryAfterMs: number } {
  const now = Date.now()
  const entry = attempts.get(key)

  if (!entry || now > entry.resetAt) {
    attempts.set(key, { count: 1, resetAt: now + WINDOW_MS })
    return { allowed: true, retryAfterMs: 0 }
  }

  entry.count++

  if (entry.count > MAX_ATTEMPTS) {
    return { allowed: false, retryAfterMs: entry.resetAt - now }
  }

  return { allowed: true, retryAfterMs: 0 }
}

setInterval(() => {
  const now = Date.now()
  for (const [k, v] of attempts) {
    if (now > v.resetAt) attempts.delete(k)
  }
}, 60_000)