Function parseIpv4

packages/core/sdk/src/hosted-http-client.ts:43–54

(hostname: string)

// these forms, so the URL path never produces one, but a resolver answer
// reaches isAllowedResolvedAddress unnormalized.
const parseIpv4 = (hostname: string): readonly [number, number, number, number] | null => {
  const parts = hostname.split(".");
  if (parts.length !== 4) return null;
  const parsed: number[] = [];
  for (const part of parts) {
    if (!/^(?:0|[1-9]\d*)$/.test(part)) return null;
    const value = Number(part);
    if (!Number.isInteger(value) || value < 0 || value > 255) return null;
    parsed.push(value);
  }
  return parsed as [number, number, number, number];
};

// `allowTrailingQuad` is the caller's statement that this segment ends the
// whole address, not merely that it ends its own half. Deciding it from the