MIGRATION-GUIDE.md

Migrating to get React SDK v1.11.0 improvements: Replacing the deprecated SplitFactory and withSplitFactory components

Starting from React SDK v1.11.0, the SplitFactoryProvider component is available and can replace the older SplitFactory and withSplitFactory components. The deprecated components will continue working, until they are removed in a future major release.

We recommend migrating to the new SplitFactoryProvider component instead. This component is a revised version of SplitFactory that properly handles SDK side effects (i.e., factory creation and destruction) within the React component lifecycle. By migrating, you can benefit from a number of improvements:

• Resolution of memory leak issues in React development mode, strict mode, and server-side rendering.

• Updating the SDK when config or factory props change.

Notable changes to consider when migrating:

• SplitFactoryProvider utilizes the React Hooks API, requiring React 16.8.0 or later, while SplitFactory is compatible with React 16.3.0 or later.

• When using the config prop with SplitFactoryProvider, the factory and client properties in SplitContext and the manager property in useSplitManager results are null in the first render, until the context is updated when some event is emitted on the SDK main client (ready, ready from cache, timeout, or update, depending on the configuration of the updateOn<Event> props of the component). This differs from the previous behavior where factory, client, and manager were immediately available. Nonetheless, it is not recommended to use the client and factory properties directly as better alternatives are available. For example, use the useTrack and useSplitTreatments hooks rather than the client's track and getTreatments methods.

• Updating the config prop in SplitFactoryProvider reinitializes the SDK with the new configuration, while SplitFactory does not reinitialize the SDK. You should pass a reference to the configuration object (e.g., via a global variable, useState, or useMemo) rather than a new instance on each render, to avoid unnecessary reinitializations.

• Updating the factory prop in SplitFactoryProvider replaces the current SDK instance, unlike SplitFactory where it is ignored.

To migrate your existing code, replace:

const MyApp = () => {
  return (
    <SplitFactory config={mySplitConfig}>
      <MyComponent />
    </SplitFactory>
  );
};

or

const MyApp = withSplitFactory(mySplitConfig)(MyComponent);

with:

const MyApp = () => {
  return (
    <SplitFactoryProvider config={mySplitConfig}>
      <MyComponent />
    </SplitFactoryProvider>
  );
};

and consider that factory, client and manager properties might be null until the SDK has emitted some event:

const MyComponent = () => {
  // factoryFromContext === factory, clientFromContext === client, and they are null until some SDK event is emitted
  const { factory: factoryFromContext, client: clientFromContext } = useContext(SplitContext);
  const { factory, client } = useSplitClient();

  // Example to evaluate all your flags when the SDK is ready and re-evaluate on SDK_UPDATE events
  const { manager } = useSplitManager();
  const FEATURE_FLAG_NAMES = manager ? manager.names() : [];
  const { treatments, isReady } = useSplitTreatments({ names: FEATURE_FLAG_NAMES, updateOnSdkUpdate: true }); // updateOnSdkReady is true by default

  return isReady ?
    treatments['feature-flag-1'].treatment === 'on' ?
      <FeatureOn /> :
      <FeatureOff /> :
    <LoadingPage />
}

Migrating to get React SDK v1.10.0 improvements: Replacing the deprecated useClient, useTreatments, and useManager hooks

Starting from React SDK v1.10.0, the useSplitClient, useSplitTreatments, and useSplitManager hooks are available and can replace the older useClient, useTreatments, and useManager hooks respectively. The deprecated hooks will continue working, until they are removed in a future major release.

We recommend migrating to the new versions useSplitClient, useSplitTreatments and useSplitManager respectively, which provide a more flexible API:

• They accept an options object as parameter, instead of a list of parameters as their deprecated counterparts. The options object can contain the same parameters as the old hooks, plus some extra optional parameters: updateOnSdkReady, updateOnSdkReadyFromCache, updateOnSdkTimedout, and updateOnSdkUpdate, which control when the hook updates the component. For example, you can set updateOnSdkUpdate to true, which is false by default, to update the component when an SDK_UPDATE event is emitted. This is useful when you want to avoid unnecessary re-renders of your components.

• They return an object containing the SDK status properties. These properties are described in the 'Subscribe to events and changes' section and enable conditional rendering of components based on the SDK status, eliminating the need to access the Split context or use the client's ready promise or event listeners. For example, you can show a loading spinner until the SDK is ready, and use the treatments result to render the variants of your app once the SDK is ready.

The usage of the new hooks is shown below:

const { client, isReady, isReadyFromCache, hasTimedout, lastUpdate } = useSplitClient({ splitKey: userId, updateOnSdkUpdate: true });
const { treatments, isReady, isReadyFromCache, hasTimedout, lastUpdate } = useSplitTreatments({ names: ['feature-flag-1'], updateOnSdkTimedout: false });
const { manager, isReady, isReadyFromCache, hasTimedout, lastUpdate } = useSplitManager();

To migrate your existing code, replace:

const client = useClient(optionalSplitKey, optionalTrafficType, optionalAttributes);
const treatments = useTreatments(featureFlagNames, optionalAttributes, optionalSplitKey);
const manager = useManager();

with:

const { client } = useSplitClient({ splitKey: optionalSplitKey, trafficType: optionalTrafficType, attributes: optionalAttributes });
const { treatments } = useSplitTreatments({ names: featureFlagNames, attributes: optionalAttributes, splitKey: optionalSplitKey });
const { manager } = useSplitManager();

and use the status properties to conditionally render your components. For example, use the following code:

const MyComponent = ({ userId }) => {

  const { treatments, isReady } = useSplitTreatments({ names: [FEATURE_X], splitKey: userId })

  return isReady ?
    treatments[FEATURE_X].treatment === 'on' ?
      <FeatureOn /> :
      <FeatureOff /> :
    <LoadingPage />
}

instead of:

const MyComponent = ({ userId }) => {

  const [sdkIsReady, setSdkIsReady] = useState(false);
  const client = useClient(userId);
  const treatments = useTreatments([FEATURE_X], undefined, userId);

  useEffect(() => {
    if (client) client.ready().then(() => setSdkIsReady(true));
  }, [client]);

  return isReady ?
    treatments[FEATURE_X].treatment === 'on' ?
      <FeatureOn /> :
      <FeatureOff /> :
    <LoadingPage />
}