# readJsonFromFile

Read JSON data from a file written with [`writeJsonToFile`](/application-development/lampixjs/api/writejsontofile.md).

## Returns

(`Promise<object>`): A promise that fulfills with either `null` (in case the file does not contain valid JSON, or if the file does not exist) or an object with the contents of the file.

## Example

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

lampix.readJsonFromFile('answers.json')
  .then(console.log); // { answerToLife: 42 }
```

## 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`](/application-development/lampixjs/api/writejsontofile.md) and `readJsonFromFile` if you want to use non-blocking (asynchronous) I/O operations.

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


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://api.lampix.co/application-development/lampixjs/api/readjsonfromfile.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.