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

Question

I know react-native-fs and react-native-fetch-blob , but I'm missing simple helper functions like getFileInfo(file) .

Desired pseudo code:

let fileInfo = getFileInfo('path/to/my/file.txt');
console.log('file size: ' + fileInfo.size);
console.log('mime type: ' + fileInfo.type);
console.log('extension: ' + fileInfo.extension);

What's the proper way to get the file size, mime type and extension?

Thanks in advance!

Answer 1

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

Answer 2

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);

Answer 3

File size: This answer suits best with new CRNA client. Use File System from Expo.

import {FileSystem} from expo 

getFileSize = async fileUri => {
   let fileInfo = await FileSystem.getInfoAsync(fileUri);
   return fileInfo.size;
 };

Answer 4

You can get data about the blob with react-native-fetch-blob and use react-native-mime-types to get the extension

const res = yield RNFetchBlob.config({fileCache: false}).fetch('GET', url, {})
const blob =  yield res.blob().then((blob) => {
    mimetype.extension(blob.type)
  }
)

Answer 5

To getting file size using react-native-fetch-blob i used the following code.

Its only suitable for small size files. If you have large size files try with some other below answers

For that u need to install base-64

var base64 = require('base-64');
RNFetchBlob.fs.readFile(filePath, 'base64')
    .then((data) => {
        var decodedData = base64.decode(data);
        var bytes=decodedData.length;
        if(bytes < 1024) console.log(bytes + " Bytes");
        else if(bytes < 1048576) console.log("KB:"+(bytes / 1024).toFixed(3) + " KB");
        else if(bytes < 1073741824) console.log("MB:"+(bytes / 1048576).toFixed(2) + " MB");
        else console.log((bytes / 1073741824).toFixed(3) + " GB");
    })

Explanation:

1. The above code decode the base64 data to string like atob().
2. Next finding length of string
3. From that value i have to calculate the file size.

If the file is too large use RNFetchBlob.fs.readStream method instead of RNFetchBlob.fs.readFile

I am getting bytes calculation from SO convert size

The code may be too long to calculate file size. If anyone found easiest way guide me