Downloading image file with react native fetch blob - react-native

Question

I am trying to learn react native and how to download files to the device. I know you can do this with react native file system but that does not support authentication which I need. React native fetch blob does support this.
For education purposes, I want to have the code from the first answer to this question recreated in react native fetch blob instead of react native file system.
I someone could write sutch an examlple form me I would be super tankfull.
Question: Downloading data files with React Native for offline use

Answer 1

Try this, it's work fine on Android:
export const download = (url, name) => {
const { config, fs } = RNFetchBlob;
let PictureDir = fs.dirs.PictureDir;
let options = {
fileCache: true,
addAndroidDownloads: {
useDownloadManager: true,
notification: true,
path: PictureDir + name,
description: t('downloading_file')
}
};
config(options)
.fetch('GET', url)
.then(res => {
if (res.data) {
alert(t('download_success'));
} else {
alert(t('download_failed'));
}
});
};

Answer 2

downloadImage(){
var date = new Date();
var url = "http://debasish.com/image.jpg";
var ext = this.getExtention(url);
ext = "."+ext[0];
const { config, fs } = RNFetchBlob ;
let PictureDir = fs.dirs.PictureDir
let options = {
fileCache: true,
addAndroidDownloads : {
useDownloadManager : true,
notification : true,
path: PictureDir + "/image_"+Math.floor(date.getTime()
+ date.getSeconds() / 2)+ext,
description : 'Image'
}
}
config(options).fetch('GET', url).then((res) => {
Alert.alert("Download Success !");
});
}
getExtention(filename){
return (/[.]/.exec(filename)) ? /[^.]+$/.exec(filename) :
undefined;
}