Function extractRetryAfterMs

packages/providers/src/retry.ts:196–220

(err: unknown)

}

function extractRetryAfterMs(err: unknown): number | undefined {
  if (typeof err !== 'object' || err === null) return undefined;
  const headers =
    (err as { headers?: Record<string, string | string[] | undefined> }).headers ??
    (err as { response?: { headers?: Record<string, string | string[] | undefined> } }).response
      ?.headers;
  const direct = (err as { retryAfter?: unknown }).retryAfter;
  const raw =
    pickHeader(headers, 'retry-after') ??
    (typeof direct === 'string' || typeof direct === 'number' ? String(direct) : undefined);
  if (raw === undefined) return undefined;
  const trimmed = raw.trim();
  // Empty / whitespace-only headers must not coerce to 0 via Number(''),
  // which would otherwise emit a zero-delay retry hint and defeat backoff.
  if (trimmed.length === 0) return undefined;
  // Numeric path first — explicit shape so '7' / '1.5' parse but a
  // Date-formatted header ('Wed, 21 Oct 2015 …') falls through to Date.parse.
  if (/^-?\d+(?:\.\d+)?$/.test(trimmed)) {
    const seconds = Number(trimmed);
    if (Number.isFinite(seconds)) return Math.max(0, seconds * 1000);
  }
  const dateMs = Date.parse(trimmed);
  if (Number.isFinite(dateMs)) return Math.max(0, dateMs - Date.now());
  return undefined;
}

function pickHeader(
  headers: Record<string, string | string[] | undefined> | undefined,