Function getHeaderBasedEarlyWarning

src/services/claudeAiLimits.ts:255–294

* Check if early warning should be triggered based on surpassed-threshold header. * Returns ClaudeAILimits if a threshold was surpassed, null otherwise.

(
  headers: globalThis.Headers,
  unifiedRateLimitFallbackAvailable: boolean,
)

 * Returns ClaudeAILimits if a threshold was surpassed, null otherwise.
 */
function getHeaderBasedEarlyWarning(
  headers: globalThis.Headers,
  unifiedRateLimitFallbackAvailable: boolean,
): ClaudeAILimits | null {
  // Check each claim type for surpassed threshold header
  for (const [claimAbbrev, rateLimitType] of Object.entries(
    EARLY_WARNING_CLAIM_MAP,
  )) {
    const surpassedThreshold = headers.get(
      `anthropic-ratelimit-unified-${claimAbbrev}-surpassed-threshold`,
    )

    // If threshold header is present, user has crossed a warning threshold
    if (surpassedThreshold !== null) {
      const utilizationHeader = headers.get(
        `anthropic-ratelimit-unified-${claimAbbrev}-utilization`,
      )
      const resetHeader = headers.get(
        `anthropic-ratelimit-unified-${claimAbbrev}-reset`,
      )

      const utilization = utilizationHeader
        ? Number(utilizationHeader)
        : undefined
      const resetsAt = resetHeader ? Number(resetHeader) : undefined

      return {
        status: 'allowed_warning',
        resetsAt,
        rateLimitType: rateLimitType as RateLimitType,
        utilization,
        unifiedRateLimitFallbackAvailable,
        isUsingOverage: false,
        surpassedThreshold: Number(surpassedThreshold),
      }
    }
  }

  return null
}

/**
 * Check if time-relative early warning should be triggered for a rate limit type.