HarmonyOS 将文件转成流

import { BusinessError } from '@ohos.base';
import fs, { WriteOptions } from '@ohos.file.fs';
let filePath = pathDir + "/test.txt";
let stream = fs.createStreamSync(filePath, "r+");
let writeOption: WriteOptions = {
  offset: 5,
  length: 5,
  encoding: 'utf-8'
};
stream.write("hello, world", writeOption).then((number: number) => {
  console.info("write succeed and size is:" + number);
  stream.close();
}).catch((err: BusinessError) => {
  console.error("write failed with error message: " + err.message + ", error code: " + err.code);
});

相关文档：

https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-file-fs-V5#ZH-CN_TOPIC_0000001847210116__write