Realm returns empty data field

Hi there,

Goals I try am trying to save an image to realm and then read it.

Expected results The database query should return the ArrayBuffer which represents the data of the image.

Actual results Saving the ArrayBuffer seems to work as realm.create returns a valid object. When trying to read the image from the database, it only returns the id field, but the image data is empty.

Steps to reproduce Save an ArrayBuffer and then read it.

Code

import Realm from 'realm';
import { encode, decode } from 'base64-arraybuffer';

const PlantSchema = {
  name: 'Plant',
  properties: {
    id:     'int',
    image:  'data'
  }
};

let realm = new Realm({schema: [PlantSchema]});

class Plant {

  getPlantImage(id) {
    const plants = realm.objects('Plant').filtered(`id == ${id}`);
    console.log(plants[0].image); // { '0': { id: 12, image: {} } }
    ...
  }

  save(id, imageData) {
    const decoded = decode(imageData); //base64 to ArrayBuffer
    realm.write(() => {
      let plant = realm.create('Plant', {
        id: id,
        image: decoded
      });
      console.log('saved: ' + plant.image); // prints saved: [object ArrayBuffer]
    });
  }
}

Versions

• Realm: 0.15.0
• react-native: 0.38.0
• react: 15.4.1
• Xcode: 8.1
• iPhone 6 Simulator
• OSX: 10.12.1

Thanks a lot Tobias

[alax]

So do data fields just not work in Realm JS at all? The issue is still present on 2.3, and it looks like this bug has been open for over a year.

Update: There doesn’t seem to be any issues with the Node version, just React Native.

Update 2: The issue seems to be related to the fact that Buffer is not present in React Native. In order to get access to data fields and work around this issue, you can do this:

1. First, install Buffer from NPM: npm install buffer (or Yarn)
2. Import Buffer: import { Buffer } from 'buffer'
3. Call Buffer.from() on your data field. Using the original post, you’d call:

const realmData = Buffer.from(plants[0].image)

1. Now, realmData will contain your previously saved image data (or whatever binary you stored.) If you need it in ArrayBuffer format, you can just use realmData.buffer which will be a Uint8Array.

Hope this helps!

[spencexyz]

I’m also having the same issue.