Null is not an object (evaluating 'RNFetchBlob.DocumentDir') using Expo

Question

I'm using Expo and try to download files using react-native-fetch-blob

import RNFetchBlob from 'rn-fetch-blob';

RNFetchBlob.fetch('GET', 'http://www.example.com/images/img1.png')
  .then((res) => {
    let status = res.info().status;
  })
  .catch((errorMessage, statusCode) => {
  })

There is an error occurs: null is not an object (evaluating 'RNFetchBlob.DocumentDir')

What i've already tried:

npm install --save react-native-fetch-blob
react-native link

npm install --save react-native-fetch-blob
react-native link react-native-fetch-blob

var RNFetchBlob = require('rn-fetch-blob').default

RNFB_ANDROID_PERMISSIONS=true react-native link

I cannot do manually linking, because i use expo and do not have /ios and /android folders.

Could anyone help, how to fix this issue? Is rn-fetch-blob work with Expo?

Did you restart the expo? If not then try again after restart expo. — Md. Robi Ullah, Jan 11 '20 at 20:06
It's just Ctrl+C and run ```npm start``` again? If so, i did it many times. — , Jan 11 '20 at 20:12
After installing new package, sometimes need to re-run project. Because expo server only recompile js part not your actual native part.. And is it works for you? — Md. Robi Ullah, Jan 11 '20 at 20:32

score 12 · Accepted Answer · answered Jan 16 '20 at 10:10

12

rn-fetch-blob doesn't work with expo.

rn-fetch-blob implements native code, and so it cannot be used in expo based projects. You would need to eject from expo

Does rn-fetch-blob work with Expo?

answered Jan 16 '20 at 10:10

Howard Wu · Answer 2 · 2020-01-11T13:34:05.733

0

add another .then before u use the result. Like this: const result= res.json()

If you need to see status, directly use res.status

edited Jan 11 '20 at 13:34

answered Jan 11 '20 at 13:22

Howard Wu

57
4

1

it didn't help unfortunately. Even if i not use any RNFetchBlob function, only one string ```import RNFetchBlob from 'rn-fetch-blob'``` causes this error – Jan 11 '20 at 18:18

score 0 · Answer 3 · answered Nov 30 '20 at 20:36

0

Change the directory to: ios and run: pod install if you have run the app from XCode on real device, re-run it again.

answered Nov 30 '20 at 20:36

Adriatik Gashi

332
4
10

Asiri Piyajanaka · Answer 4 · 2023-07-14T12:59:45.803

0

For react native after change import RNFetchBlob from 'rn-fetch-blob' to import { RNFetchBlob } from 'rn-fetch-blob'; in the node modules the error goes away.

edited Jul 14 '23 at 12:59

answered Jul 14 '23 at 11:40

Asiri Piyajanaka

41
6

Null is not an object (evaluating 'RNFetchBlob.DocumentDir') using Expo

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