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React Native Client SDK

DEPRECATED

To get started with Statsig in ReactNative, you should use the new Statsig ReactNative SDK.

This version of the SDK is deprecated and will only receive major bug fixes going forward.

If you already use this deprecated version, you should check out the migration docs.

If you are using Expo, check out our Expo SDK.

This SDK (statsig-react-native) wraps the statsig-react SDK. It contains the same React Context, Providers, and Hooks, used in the same way, HOWEVER you must import from the statsig-react-native package.

Installation​

You can install the SDK via npm or yarn. In your project directory, run:

npm install statsig-react-native

Next, let's install the dependencies we need for the SDK to work:

npm install @react-native-async-storage/async-storage react-native-device-info react-native-get-random-values

Lastly, if you are on a Mac and developing for iOS, you need to install the pods to complete the linking:

npx pod-install ios # or pod install, in your /ios folder

Initialize the SDK​

After installation, you will need to initialize the SDK using a Client SDK key from the "API Keys" tab on the Statsig console.

These Client SDK Keys are intended to be embedded in client side applications. If need be, you can invalidate or create new SDK Keys for other applications/SDK integrations.

info

Do NOT embed your Server Secret Key in client-side applications, or expose it in any external-facing documents. However, if you accidentally expose it, you can create a new one in the Statsig console.

In addition to the SDK key, you should also pass in a StatsigUser for feature gate targeting and experimentation grouping purposes.

The 3rd parameter is optional and allows you to pass in a [StatsigOptions](#statsig-options) to customize the SDK.

At the root of your component tree, wrap your app in a StatsigProvider and set waitForInitialization=true.

import { StatsigProvider } from "statsig-react-native";

function App() {
  return (
    <StatsigProvider
      sdkKey="<STATSIG_CLIENT_SDK_KEY>"
      waitForInitialization={true}
      // StatsigOptions (Not Required)
      options={{
        environment: { tier: "staging" },
      }}
    >
      <div className="App">{/* Rest of App ... */}</div>
    </StatsigProvider>
  );
}
note

If you do not use waitForInitialization, all checks to Statsig will return default values until initialization completes.

Working with the SDK​

statsig-react-native utilizes React Hooks to provide access to your gates/configs/experiments. It also exposes a global Statsig class that you can import outside your component tree to access this information.

info

Statsig SDK Hooks rely on a Context from the Statsig Provider. Context will get its value from the closest matching Provider above it in the component tree. Make sure you make a separate child component to consume the StatsigContext, and place your hooks there. Learn more here: https://reactjs.org/docs/context.html

Checking a Feature Flag/Gate​

Now that your SDK is initialized, let's check a Feature Gate. Feature Gates can be used to create logic branches in code that can be rolled out to different users from the Statsig Console. Gates are always CLOSED or OFF (think return false;) by default.

import { useGate } from "statsig-react-native";

...

function MyComponent() {
  const { value, isLoading } = useGate("a_gate_name");

  // Only required if you have not set waitForInitialization to true
  if (isLoading) {
    return <div>Fetching Values...</div>;
  }

  return <div>{value ? "Passes Gate" : "Fails Gate"}</div>;
}

Reading a Dynamic Config​

Feature Gates can be very useful for simple on/off switches, with optional but advanced user targeting. However, if you want to be able send a different set of values (strings, numbers, and etc.) to your clients based on specific user attributes, e.g. country, Dynamic Configs can help you with that. The API is very similar to Feature Gates, but you get an entire json object you can configure on the server and you can fetch typed parameters from it. For example:

import { useConfig } from "statsig-react-native";

...
function MyComponent() {
  const { config, isLoading } = useConfig("a_config_name");

  // Only required if you have not set waitForInitialization to true
  if (isLoading) {
    return <div>Fetching Values...</div>;
  }

  return <div>{config.get("header_label", "Welcome")}</div>;
}

Getting an Layer/Experiment​

Then we have Layers/Experiments, which you can use to run A/B/n experiments. We offer two APIs, but we recommend the use of layers to enable quicker iterations with parameter reuse.

import { useLayer } from "statsig-react-native";

...
function MyComponent() {
  const { layer, isLoading } = useLayer("a_layer");

  // Only required if you have not set waitForInitialization to true
  if (isLoading) {
    return <div>Fetching Values...</div>;
  }

  return (
    <div>
      <h1>{layer.get("title", "Welcome to Statsig!")}</h1>
      <p>{layer.get("discount", 0.1)}</p>
    </div>
  );
}

Logging an Event​

Now that you have a Feature Gate or an Experiment set up, you may want to track some custom events and see how your new features or different experiment groups affect these events. This is super easy with Statsig - simply call the Log Event API for the event, and you can additionally provide some value and/or an object of metadata to be logged together with the event:

import { Statsig } from 'statsig-react-native';

...

export default function MyComponent(): JSX.Element {
  return <Button
    onClick={() => {
      Statsig.logEvent("add_to_cart", "SKU_12345", {
        price: "9.99",
        item_name: "diet_coke_48_pack",
      });
    }}
  />;
}

Learn more about identifying users, group analytics, and best practices for logging events in the logging events guide.

Statsig User​

You should provide a StatsigUser object whenever possible when initializing the SDK, passing as much information as possible in order to take advantage of advanced gate and config conditions (like country or OS/browser level checks).

Most of the time, the userID field is needed in order to provide a consistent experience for a given user (see logged-out experiments to understand how to correctly run experiments for logged-out users).

If the user is logged out at the SDK init time, you can leave the `userID` out for now, and we will use a stable device ID that we create and store in the local storage for targeting purposes.

Besides userID, we also have email, ip, userAgent, country, locale and appVersion as top-level fields on StatsigUser. In addition, you can pass any key-value pairs in an object/dictionary to the custom field and be able to create targeting based on them.

const [user, setUser] = useState({
  userID: "a-user",
  email: "user-a@gmail.com"
});

...

// Pass your StatsigUser into the StatsigProvider
return (
    <StatsigProvider
      sdkKey="client-key"
      waitForInitialization={true}
      user={user}
    >

Private Attributes​

Have sensitive user PII data that should not be logged? No problem, we have a solution for it! On the StatsigUser object we also have a field called privateAttributes, which is a simple object/dictionary that you can use to set private user attributes. Any attribute set in privateAttributes will only be used for evaluation/targeting, and removed from any logs before they are sent to Statsig server.

For example, if you have feature gates that should only pass for users with emails ending in "@statsig.com", but do not want to log your users' email addresses to Statsig, you can simply add the key-value pair { email: "my_user@statsig.com" } to privateAttributes on the user and that's it!

Updating the StatsigUser​

If/when the user object changes, the SDK will automatically fetch the updated values for the new user object - if waitForInitialization is false, and no mountKey is set on the StatsigProvider, this will trigger a re-render for the new user with default values, followed by a render when the values have been updated.

setUser({ userID: "another-user" });

There also exists am updateUser method on the Statsig interface, but calling this directly may lead to issues with the StatsigProvider.

FAQ​

How do I run experiments for logged out users?​

See the guide on device level experiments

Which Browsers Supported?​

The statsig-react-native SDK relies on the statsig-js SDK and inherits its browser compatibility. For more information, see the statsig-js docs.

Why a I seeing an "unexpected exception"?​

Some users of the ReactNative SDK have reported issues that look like the following:

 ERROR  [Statsig] An unexpected exception occurred. [TypeError: undefined is not a function (near '...}).finally(function () {...')]

Some libraries, like storybook, remove the finally() handler for promises. In order to pollyfill this and get around the error, see this thread:

https://github.com/storybookjs/react-native/issues/20

Reference​

Statsig​

You can import the global Statsig singleton to call SDK functions outside of a component tree or in callbacks/loops/or wherever else you are unable to use hooks. For all SDK functions, see the statsig-js sdk docs.

caution

If you are calling methods on the global Statsig like initialize or updateUser, the user object tracked by the provider and the user object used outside the component tree can get out of sync. You are responsible for maintaining the state of the user and keeping it consistent with the StatsigProvider in these cases. The statsig-react-native SDK uses the global Statsig class to serve gate/config/experiment checks, but these are memoized in the hooks the SDK provides. Updates to the user which impact flag values that are made outside the context of the react component tree will not be reflected in the component tree unless the updated user is passed in to the StatsigProvider.

StatsigProvider​

StatsigProvider is a react context provider which initializes the SDK, and passes down its state to the rest of the react application via a StatsigContext. It takes the following properties:

  • children: React.ReactNode | React.ReactNode[]; - One or more child components
  • sdkKey: string; - A client SDK key from the Statsig Console
  • user: StatsigUser; - A Statsig User object. Changing this will update the user and Gate values, causing a re-initialization
  • options?: StatsigOptions; - See StatsigOptions. An optional bag of initialization properties (shared with the statsig-js sdk) for advanced configuration.
  • waitForInitialization?: boolean; - Waits for the SDK to initialize with updated values before rendering child components
  • initializingComponent?: React.ReactNode | React.ReactNode[]; - A loading component to render iff waitForInitialization is set to true and the SDK is initializing
  • mountKey?: string - A key for stable mounting/unmounting when updating the user. If this key is set and changes when the user object changes (or if it is not provided) Then the children of StatsigProvider will unmount/remount with the async update. If this key is set and does not change, then the children of StatsigProvider will continue to be mounted, and it will trigger a rerender after updateUser completes.
  • shutdownOnUnmount?: boolean - If set to true, will automatically call Statsig.shutdown() when the provider is unmounted

StatsigContext​

StatsigContext is a react context used internally by the SDK to manage internal state. You should not need to use the StatsigContext directly, as the Provider and Hooks interface with it for you. It tracks the following state:

  • initialized: boolean; the initialization state of the SDK
  • statsigPromise: React.MutableRefObject<Promise<void>> | null; a reference to a promise which resolves once SDK initialization is complete
  • initStarted: boolean whether the singleton Statsig has had initialize called on it, meaning the SDK is now usable and can serve checks from cache and queue log events
  • userVersion: number used internally by the SDK to memoize SDK functions based on the user. Increments when the user object is changed and updateUser is called.

StatsigOptions​

  • environment: StatsigEnvironment, default null
    • An object you can use to set environment variables that apply to all of your users in the same session and will be used for targeting purposes.
    • The most common usage is to set the environment tier ('production', 'staging' or 'development'), e.g. { tier: 'staging' }, and have feature gates pass/fail for specific environments.
  • disableCurrentPageLogging boolean, default false.
    • By default, the sdk appends the current page for log events to the event payload to generate user journey/funnel analytics
  • loggingIntervalMillis: number, default 5000 (5s), min 1000, max 60000
    • How frequently to flush logs to statsig (milliseconds)
  • loggingBufferMaxSize: number, default 10), min 2, max 500
    • Maximum number of events to buffer before flushing events to statsig
  • disableNetworkKeepalive: boolean, default false
    • Entirely disables the keepalive flag from being appended to network requests issued by the SDK
  • api - default https://api.statsig.com/v1/
    • The default endpoint to use for all SDK network requests. You should not override this (unless you have another API that implements the Statsig API endpoints)
    • If you wish to separately override the log_event endpoint only, see eventLoggingApi
  • overrideStableID - string, default null
    • If you'd like to use your own ID in place of Statsig's stableID, then you can pass the ID as an option here.
    • Once a value is passed, the SDK will store this ID in the local storage for the browser for future use as well.
  • localMode - boolean, default false
    • Pass true to this option to turn on Local Mode for the SDK, which will stop the SDK from issuing any network requests and make it only operate with only local overrides (If supported) and cache.
      Note: Since no network requests will be made, a dummy SDK key starting with "client-" can be used. (eg "client-key")
  • initTimeoutMs - number, default 3000
    • This option configures the maximum time (in milliseconds) the SDK would wait for the network request made by initialize() to respond before it resolves.
    • If the SDK resolves before the network request has completed due to the timeout, it will continue work with local overrides, cached values, and then default values set in code.
  • disableErrorLogging - boolean, default false
    • By default, the SDK auto logs javascript errors to Statsig. This will be connected with the metrics and pulse views to show the impact of new features on key error metrics
  • disableAutoMetricsLogging - boolean, default false
    • By default, the SDK auto logs javascript performance metrics to Statsig. This will be connected with the metrics and pulse views to show the impact of new features on key performance metrics
  • eventLoggingApi? string, default 'https://events.statsigapi.net/v1/
    • The SDK will hit different endpoints for initialize to evaluate gates and for logEvent to log event data. The api option controls the evaluation endpoint, and eventLoggingApi controls the event logging endpoint.
  • prefetchUsers? StatsigUser[] | null, default null
    • An array of additional StatsigUser objects to be fetched during the statsig.initialize call. A max of 5 users is enforced, if more than 5 users are provided, the 5 users at the start of the array will be used.

Hooks​

useGate​

A react hook to get a Statsig Feature Gate.

Parameters:

  • gateName: string - the name of the gate to check

Returns GateResult:

  • isLoading: boolean; - the loading/initializing state of the SDK
  • value: boolean - the value of the feature gate (false by default)

useConfig​

A react hook to get a Statsig Dynamic Config.

Parameters:

  • configName: string - the name of the config to get

Returns ConfigResult:

  • isLoading: boolean; - the loading/initializing state of the SDK
  • config: DynamicConfig - the backing DynamicConfig (see the statsig-js sdk docs for more information)

useExperiment​

A react hook to get a Statsig Experiment, represented as a DynamicConfig.

Parameters:

  • experimentName: string - the name of the experiment to get

Returns ConfigResult:

  • isLoading: boolean; - the loading/initializing state of the SDK
  • config: DynamicConfig - the backing DynamicConfig (see the statsig-js sdk docs for more information)

useLayer​

A react hook to get a Statsig Experiment, represented as a Layer.

Parameters:

  • experimentName: string - the name of the experiment to get

Returns LayerResult:

  • isLoading: boolean; - the loading/initializing state of the SDK
  • layer: Layer - the backing Layer (see the statsig-js sdk docs for more information)

useStatsigLogEffect​

A react hook to simplify top level logEvents into an effect which will only log and event once the SDK is ready

Parameters:

  • eventName: string
  • value?: string | number | null
  • metadata?: Record<string, string> | null