HarmonyOS如何获取app缓存的文件大小（图片、文件、其他一些文件等），显示xxMB

import fs from '@ohos.file.fs'; 
import { Context } from '@kit.AbilityKit'; 
import { BusinessError } from '@ohos.base'; 
clearCache() { 
  const context: Context = getContext(this); 
  let cacheDir = context.cacheDir 
  fs.listFile(cacheDir).then((filenames) => { 
    for (let i = 0;i < filenames.length; i++) { 
      let dirPath = cacheDir+filenames[i] 
      try { 
        // 判断是否文件夹 
        let isDirectory = fs.statSync(dirPath).isDirectory() 
        if (isDirectory) { 
          fs.rmdirSync(dirPath) 
        } else { 
          fs.unlink(dirPath).then(() => { 
            console.info('remove file succeed'); 
          }).catch((err: BusinessError) => { 
            console.info("remove file failed with error message: " + err.message + ", error code: " + err.code); 
          }); 
        } 
      }catch (e) { 
        console.log(e) 
      } 
    } 
  }) 
}