HarmonyOS Map<string,object>这种形式的转为Json

function mapToString(map: Map<string, string | object>): string { 
  if (map.size === 0) { 
    return ''; 
  } 
 
  let obj: object = new Object; 
  map.forEach((value, key) => { 
    if (value instanceof Map) { 
      obj[key] = mapToString(value); 
    }else { 
      obj[key] = value; 
    } 
  }) 
  return JSON.stringify(obj); 
}