registerAllFlagsListener passes a JSON string to its handler, not an array of flags

[vcarl]

Is this a support request?
no

Describe the bug
An "all flags" listener is being passed a string representation of a JSON array, not the array itself (which is what the TS types specify it receives).

const handler = (allFlags) => {
  console.log({ allFlags })
}
client.registerAllFlagsListener(handlerId, handler);
// assuming a flag called `'feature-flag'`, what's logged is:
// {"allFlags": "[\"feature-flag\"]"}

To reproduce
see above

Expected behavior
Argument values match their TS types

Logs
n/a

SDK version
4.0.3

Language version, developer tools
React native, I'm not sure what JS version the device is running

OS/platform
Android 11 simulator, Pixel 2 emulator

Additional context
Add any other context about the problem here.

[gwhelanLD]

This issue was fixed in the 5.0.1 release of the SDK. Is it possible for you to update to that version? If not, we can investigate back-porting that fix to the 4.0 SDK.

Thanks,
@gwhelanLD

[vcarl]

Should be able to update, thanks for the quick response. I'll close out.

While I'm here, the RN docs for "subscribing to updates" are extremely unhelpful. The code sample doesn't actually retrieve the update value, it just stores what flags have changed (in a super non-idiomatic manner), while variable names imply that it's the value itself being passed to the handler.

if (this.state.listeners.hasOwnProperty(key)) {
  return;
}
let listener = value => Alert.alert('Listener Callback', value);
client.registerFeatureFlagListener('MY_LISTEN_FLAG_KEY', listener);
this.setState({listeners: {...this.state.listeners, ...{['MY_LISTEN_FLAG_KEY']: listener}}});

https://docs.launchdarkly.com/sdk/features/flag-changes#react-native

I settled on a solution that looks like this (with some abstractions collapsed), but I found it very complicated to actually retrieve the updated value.

const experiments = {
  ["some-flag"]: {
    defaultValue: true,
  } /* an object of flag names/defaults */,
};

const handler = async (allFlags) => {
  const newValues = await Promise.all(
    allFlags.map(async (flag) => {
      const { defaultValue } = experiments[flag];
      switch (typeof defaultValue) {
        case "string":
          return {
            name,
            value: await client.stringVariation(flag, defaultValue),
          };
        case "boolean":
          return {
            name,
            value: await client.boolVariation(flag, defaultValue),
          };
        case "number":
          return {
            name,
            value: await client.intVariation(flag, defaultValue),
          };
      }
    })
  );
}
client.registerAllFlagsListener(handlerId, handler);