harmony 鸿蒙Single I/O Task Development

2023-10-30
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Single I/O Task Development

Asynchronous concurrency provided by Promise and async/await is applicable to the development of a single I/O task. The following uses the asynchronous concurrency capability to write a file as an example.

Implement the logic of a single I/O task.

import fs from '@ohos.file.fs';
import { BusinessError } from '@ohos.base';
async function write(data: string, filePath: string): Promise<void> {
  let file: fs.File = await fs.open(filePath, fs.OpenMode.READ_WRITE);
  fs.write(file.fd, data).then((writeLen: number) => {
    fs.close(file);
  }).catch((err: BusinessError) => {
    console.error(`Failed to write data. Code is ${err.code}, message is ${err.message}`);
  })
}

Use the asynchronous capability to invoke the single I/O task. For details about how to obtain filePath in the example, see Obtaining Application File Paths.
```
let filePath: string = "path"; // Application file path
write('Hello World!', filePath).then(() => {
  console.info('Succeeded in writing data.');
})
```