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launchdarkly.com

React Native SDK reference

Read time: 7 minutes
Last edited: Dec 10, 2024
Recent major versions

Version 10 of the React Native SDK has been rewritten in pure TypeScript and is compatible with Expo. Only iOS and Android platforms are supported. Web is not supported. Version 10 is a rewrite of the React Native SDK. It is based on the JavaScript SDK, and it replaces launchdarkly-react-native-client-sdk. To learn more about upgrading, read React Native SDK 9.x to 10.0 migration guide.


Version 9 of the React Native SDK includes updated dependencies. If you are upgrading from version 8 or below, we recommend upgrading directly to version 10. To learn more about version 9 specifically, read React Native SDK 8.x to 9.0 migration guide.


Version 8 of the React Native SDK introduces optional automatic collection of environment attributes. To learn more about upgrading, read React Native SDK 7.x to 8.0 migration guide.

Overview

This topic documents how to get started with the React Native SDK, and links to reference information on all of the supported features.

SDK quick links

LaunchDarkly's SDKs are open source. In addition to this reference guide, we provide source, API reference documentation, and sample applications:

ResourceLocation
SDK API documentationSDK API docs
GitHub repositoryreact-native
Sample Expo applicationReact Native
Published modulenpm

Get started

After you complete the Get started process, follow these instructions to start using the LaunchDarkly SDK in your React Native code:

  • Understand version compatibility
  • Install the SDK
  • Initialize the client and identify a context

Understand version compatibility

Expo usage

The LaunchDarkly React Native client-side SDK version 10.x is compatible with Expo. Only iOS and Android platforms are supported. Web is not supported.


Earlier versions of the LaunchDarkly React Native SDK are not compatible with the Expo managed workflow because they use native modules. Consider upgrading to the 10.x version of the LaunchDarkly SDK, or using the bare workflow instead.

The following table describes the LaunchDarkly React Native SDK version compatibility:

LaunchDarkly React Native SDK versionCompatible with
10.xReact Native 0.72, 0.73, 0.74, 0.76; Expo 51, Expo 52
9.xReact Native 0.73
8.xReact Native 0.69 through 0.72
7.xReact Native 0.69
6.xXcode 12.2 or higher and React Native 0.64

If you need support for earlier versions of React Native, use older versions of the LaunchDarkly React Native SDK. To learn more, read Releases.

Install the SDK

To install the SDK:

  1. Install the LaunchDarkly SDK as a dependency.
  1. The LaunchDarkly React Native SDK version 10 uses @react-native-async-storage/async-storage for bootstrapping:

  • If you are using Expo, skip this step and continue to step 3.

  • If you are not using Expo, you must explicitly add @react-native-async-storage/async-storage as a dependency to your project.

  1. Run npx pod-install.

  2. Next, import the SDK into your project:

The React Native SDK uses a mobile key

The React Native SDK uses a mobile key. Keys are specific to each project and environment. They are available from the Environments list for each project. To learn more about key types, read Keys.


Mobile keys are not secret and you can expose them in your client-side code without risk. However, never embed a server-side SDK key into a client-side application.

  1. After the SDK is imported, create a single, shared instance of ReactNativeLDClient. To create this, you need your environment's mobile key. This authorizes your application to connect to a particular environment within LaunchDarkly.

  2. After you instantiate ReactNativeLDClient, pass it to LDProvider. LDProvider uses the React context API to store and pass data to child components through hooks. It requires the client.

Initialize the client and identify a context

In version 10 of the SDK, you do not specify a context when you initialize the client. Instead, you must provide the context in an identify() call, for example on application mount. The identify() method returns a promise that can be awaited. End users will receive fallback values until you specify a context by calling identify().

Always include a timeout parameter

Do not configure your SDK to initialize without a timeout parameter. Doing so will cause your app never to load if there is a connectivity problem. We recommend setting a timeout for no more than 1-5 seconds.

In v10, the identify timeout defaults to 5 seconds. In older versions, the client.configure takes a timeout parameter.

The following example shows the simplest way to create a shared instance of ReactNativeLDClient, and identify a context:

To learn more about the specific configuration options available in this SDK, read LDOptions.

ReactNativeLDClient should be a singleton

We recommend making ReactNativeLDClient a singleton for each LaunchDarkly project. The client instance maintains internal state that allows LaunchDarkly to serve feature flags without making any remote requests.

Making feature flags available to this SDK

You must make feature flags available to mobile SDKs before the SDK can evaluate those flags. If an SDK tries to evaluate a feature flag that is not available, LaunchDarkly serves the fallback value for that flag.

To make a flag available to this SDK, check the SDKs using Mobile key checkbox during flag creation, or on the flag's settings page. To make all of a project's flags available to this SDK by default, check the SDKs using Mobile key checkbox on your project's Flag settings page.

Background fetch

In version 10, the React Native SDK defaults to a streaming connection mode. In this mode, your application receives updates when it is in the foreground and does not when it is in the background. To learn more, read Offline mode.

In previous versions, the SDK defaulted to the background fetch behavior for the platform it was running on.

Shut down the client

Shut down the client when your application terminates. To learn more, read Shutting down.

Data collection

To learn more about data collection within this SDK and implications on submissions to the Apple App Store, read Apple App Store data collection policy.

Supported features

This SDK supports the following features: