> For the complete documentation index, see [llms.txt](https://api.lampix.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://api.lampix.co/application-development/lampixjs/api/writejsontofile.md).

# writeJsonToFile

Write JSON data to a file to retrieve later via [`readJsonFromFile`](/application-development/lampixjs/api/readjsonfromfile.md).

## Returns

(`Promise<void>`): A promise that fulfills without arguments when writing has finished.

## Example

```javascript
import lampix from '@lampix/core';

const data = {
  answerToLife: 42
};

lampix.writeJsonToFile('answers.json', data)
  .then(() => console.log('Successfully saved all answers.'));
```

## Notes

[`localStorage`](https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage) API is also enabled. You can use it instead of this method. `localStorage`, by design, is a blocking I/O operation (synchronous). Use `writeJsonToFile` and [readJsonFromFile](/application-development/lampixjs/api/readjsonfromfile.md) if you want to use non-blocking (asynchronous) I/O operations.

`writeJsonToFile` (like `localStorage`), is application specific. This means one application cannot retrieve the saved data of another application.