export function stringOrNull(value: unknown): string | null {
  return typeof value === "string" && value.trim() ? value.trim() : null;
}

export function normalizeArray(values: readonly string[] | undefined): string[] {
  return (values ?? []).map((value) => value.trim()).filter(Boolean);
}

export function parseStringArray(value: unknown): string[] {
  if (!Array.isArray(value)) {
    return [];
  }
  return value.filter(
    (entry): entry is string => typeof entry === "string" && entry.trim().length > 0,
  );
}

export function coerceNumber(value: unknown, field: string): number {
  if (typeof value === "number" && Number.isFinite(value)) {
    return value;
  }
  throw new Error(`Receipt field ${field} must be a finite number`);
}

export function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null;
}