React native: how to get file size, mime type and extension?

In react-native-fs you can use the stat method (to get the file size)

import { stat } from 'react-native-fs';

...

const statResult = await stat('path/to/my/file.txt');
console.log('file size: ' + statResult.size);

With react-native-fetch-blob, you can get the file size with the code below:

RNFetchBlob.fs.stat(PATH_OF_THE_TARGET)
.then((stats) => {})
.catch((err) => {})

The response stats contains the following info:

{
     // file name
     filename : 'foo.png',
     // folder of the file or the folder itself
     path : '/path/to/the/file/without/file/name/',
     // size, in bytes
     size : 4901,
     // `file` or `directory`
     type : 'file',
     // last modified timestamp
     lastModified : 141323298
}

Source: https://github.com/wkh237/react-native-fetch-blob/wiki/File-System-Access-API#user-content-statpathstringpromisernfetchblobstat