React Native save base64 image to Album

Question

Third Party API return a "QR code image" in base64 encode,
I need save that image to User's Album.

• CamerRoll - not support saving base64 image to album
• React-Native-Fetch-Blob - https://github.com/wkh237/react-native-fetch-blob
  still looking into it
• React-Native-fs - https://github.com/itinance/react-native-fs
  I am trying this now
• There are few npm modules with very little Github star (<10)

the React-Native-Fetch-Blob maintainer gone missing, so no one answering Github Issue, createFile from React-Native-Fetch-Blob Document not working as expected(not saving image into album)

  import fetch_blob from 'react-native-fetch-blob';

  // json.qr variable are return from API

  const fs = fetch_blob.fs
  const base64 = fetch_blob.base64
  const dirs = fetch_blob.fs.dirs

  const file_path = dirs.DCIMDir + "/some.jpg"
  const base64_img = base64.encode(json.qr)

  fs.createFile(file_path, base64_img, 'base64')
  .then((rep) => { 
    alert(JSON.stringify(rep));
  })
  .catch((error) => {
    alert(JSON.stringify(error));
  });

Anyone deal with this problem before?

How to save a base64 encode Image string to User album? (as a jpg or png file)

because I fetch an API with no CORS header,
I can't debug it in Debug JS Remotely
Chrome would stop that request from happening,

I have to run that on my Android Phone to make it work
(no CORS control on real phone)

I am planing use Clipboard save base64 string,
and hardcode it in my code,
to debug what's wrong with react-native-fetch-blob createFile API

Answer 1

Remove data:image/png;base64, in your base64 string

var Base64Code = base64Image.split("data:image/png;base64,"); //base64Image is my image base64 string

const dirs = RNFetchBlob.fs.dirs;

var path = dirs.DCIMDir + "/image.png";

RNFetchBlob.fs.writeFile(path, Base64Code[1], 'base64')
.then((res) => {console.log("File : ", res)});

And then I solved my problem.

Answer 2

I solve the problem,
turn out I forgot data:image/png;base64, at beginning of the string.

I remove it with following code

  // json.qr is base64 string
  var image_data = json.qr.split('data:image/png;base64,');
  image_data = image_data[1];

and then save the image file

  import fetch_blob from 'react-native-fetch-blob';
  import RNFS from 'react-native-fs';

  const fs = fetch_blob.fs
  const dirs = fetch_blob.fs.dirs      
  const file_path = dirs.DCIMDir + "/bigjpg.png"

  // json.qr is base64 string "data:image/png;base64,..."

  var image_data = json.qr.split('data:image/png;base64,');
  image_data = image_data[1];

  RNFS.writeFile(file_path, image_data, 'base64')
  .catch((error) => {
    alert(JSON.stringify(error));
  });

I wrote a blog about this

http://1c7.me/react-native-save-base64-image-to-album/