HarmonyOS 如果获取一个文件的大小

获取到沙箱地址，通过fs.stat()可以查看，API地址：

https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-file-fs-V5#fsstat

import { BusinessError } from '@ohos.base';
let filePath = pathDir + "/test.txt";
fs.stat(filePath).then((stat: fs.Stat) => {
  console.info("get file info succeed, the size of file is " + stat.size);
}).catch((err: BusinessError) => {
  console.error("get file info failed with error message: " + err.message + ", error code: " + err.code);
});