Made of little things.

type NappletWindow = Window & {
    napplet?: Record<string, unknown>;
};

/** Return whether the runtime injected a domain for this load. */
export function hasDomain(napplet: Record<string, unknown> | undefined, domain: string): boolean {
    return Boolean(napplet?.[domain]);
}

/** Check a domain on the runtime-owned global without exposing it for calls. */
export function runtimeHasDomain(domain: string): boolean {
    return hasDomain((window as NappletWindow).napplet, domain);
}