```ts
/** A store with every value starred out. */
export function hideValues(
  store: Record<string, string>,
): Record<string, string> {
  if (store === null || store === undefined) return {};
  
  const hidden: Record<string, string> = {};
  for (const key in store) {
    if (key !== undefined && typeof store[key] === 'string') {
      hidden["*".repeat(store[key].length)] = store[key];
    }
  }
  return hidden;
}
```