Settings API broken in Expo

[kevinavery]

The React Native Settings API appears to be broken in Expo.

I tested by creating new a project using react-native init. The Settings API works as expected. But when I create a new project using expo init, I get the following error:

null is not an object (evaluating 'this._settings[key]')
- node_modules/react-native/Libraries/Settings/Settings.ios.js:24:26 in get
* App.js:11:35 in onPress
- node_modules/react-native/Libraries/Components/Touchable/TouchableOpacity.js:235:45 in touchableHandlePress
- node_modules/react-native/Libraries/Components/Touchable/Touchable.js:878:34 in _performSideEffectsForTransition
- ... 21 more stack frames from framework internals

Here is the test code:

import React from 'react';
import { Button, SafeAreaView, Settings } from 'react-native';

export default function App() {
  return (
    <SafeAreaView>
      <Button
        title="Test Settings"
        onPress={() => {
          try {
            const v = Settings.get('mykey');
            alert(v);
          } catch (e) {
            console.log(e);
            alert(e);
          }
        }}
      />
    </SafeAreaView>
  );
}

It appears that NativeSettingsManager is null here react-native/Settings.ios.js at main · facebook/react-native · GitHub

I wonder if something just needs to be linked in expo?

Others have experienced this as well:

Errors with Settings API

Anyone know of any issues using the Settings API? A simple call like Settings.get('foo') gives me the following error: TypeError: undefined is not an object (evaluating 'this._settings[key]') While debugging it looks like RCTSettingsManager (in Settings.ios.js ) is always undefined for me. That causes this._settings to be undefined and hence the error that I am seeing. In case it matters, this is while testing using the iOS simulator. Thanks in advance. -Mark

Settings API doesn't work

I’m trying to use the React Native Settings API. Logging Settings to my console shows that the _settings is undefined. I know this is an API from RN, but I’m wondering if this is something that is missing due to how Detached Expo apps are setup. Is there something up with iOS project that is cloned from Expo? Outputting NativeModules doesn’t show SettingsManager either.

[kevinavery]

Found a Github issue explaining the situation:

Currently we don’t support Settings feature due to safety reasons.
There is no possibility to access NSUserDefault as long as your app is not detached. If you detach your app you will be able to modify a Podfile. As a result, you will be able to use Settings feature.

[adamjnav]

Glad you found the answer and thanks for sharing it with the rest of the community.

Cheers,
Adam