@rnx-kit/react-native-host


@rnx-kit/react-native-host simplifies React Native initialization.

The aim of this package is to provide a backwards (and forwards) compatible way
of initializing React Native, regardless of whether you're on New Architecture
or have gone fully bridgeless.@rnx-kit/react-native-host will also a provide a
simple way to enable split bundles and service delivery.

Installation

``sh
yarn add @rnx-kit/react-native-host --dev
`

or if you're using npm

`sh
npm add --save-dev @rnx-kit/react-native-host
`

Usage

$3

> [!NOTE]
>
> For a working example how to use this library for iOS/macOS, see
> react-native-test-app.

To avoid accidental autolinking, @rnx-kit/react-native-host must be manually
linked. In your Podfile, add the following line:

`rb
pod 'ReactNativeHost', :path => '../node_modules/@rnx-kit/react-native-host'
`

Adjust the path accordingly to your project setup. If you prefer a more dynamic
approach, you can also try using this script:

`rb
proj_dir = Pathname.new(__dir__)
proj_dir = proj_dir.parent until
File.exist?("#{proj_dir}/node_modules/@rnx-kit/react-native-host/ReactNativeHost.podspec") ||
proj_dir.expand_path.to_s == '/'

pod 'ReactNativeHost', :path => "#{proj_dir}/node_modules/@rnx-kit/react-native-host"
`

Run pod install at least once to make sure it gets added to your project. Then
make the following changes:

- Replace instances of RCTBridgeDelegate with RNXHostConfig. The latter is a
superset and is backwards compatible.
- Replace instantiation of RCTBridge with ReactNativeHost. ReactNativeHost
will instantiate the appropriate modules required for your setup. It will also
handle New Architecture configuration as necessary.
- Instead of instantiating RCTRootView directly, use
-[ReactNativeHost viewWithModuleName:initialProperties:] to create your root
views.

For example, if you previously had something like this:

`objc
// AppDelegate.h
@import React;
@import UIKit;

@interface AppDelegate : UIResponder
@end

// AppDelegate.m
@implementation AppDelegate {
RCTBridge *_bridge;
}

- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
...

_bridge = [[RCTBridge alloc] initWithDelegate:self
launchOptions:launchOptions];
RCTRootView *rootView = [[RCTRootView alloc] initWithBridge:_bridge
moduleName:moduleName
initialProperties:initialProperties];

...
}

@end
`

You should instead have:

`objc
// AppDelegate.h
@import ReactNativeHost;
@import UIKit;

@interface AppDelegate : UIResponder
@end

// AppDelegate.m
@implementation AppDelegate {
ReactNativeHost *_host;
}

- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
...

_host = [[ReactNativeHost alloc] initWithConfig:self];
UIView *rootView = [_host viewWithModuleName:moduleName
initialProperties:initialProperties];

...
}

@end
`

API

$3

Instantiates the appropriate modules required for the setup. It handles New
Architecture if necessary.

#### initWithConfig:

Swift name: init(_:)

Creates an instance of ReactNativeHost using the designated initializer.

Objective-C:

`objc
ReactNativeHost *host = [[ReactNativeHost alloc] initWithConfig:self];
`

Swift:

`swift
let host = ReactNativeHost(config: self)
`

#### shutdown

Shuts down the React Native instance

#### usingModule:block:

Swift name: using(module:block:)

Retrieves or initializes a desired native module. Parameters:

- moduleClass - class of the native module to initialize or retrieve
- block - block that gets called when the native module is retrieved

Objective-C:

`objc
[host usingModule:[MyNativeModuleClass class] block:^(id module) {
if (![module isKindOfClass:[MyNativeModuleClass class]]) {
return;
}
MyNativeModuleClass myNativeModule = (MyNativeModuleClass )module;
// Use the native module here
}];
`

Swift:

`swift
host.using(module: MyNativeModuleClass.self) {
guard let myNativeModule = module as? MyNativeModuleClass else {
return
}
// Use the native module here
}
`

#### hostFromRootView:

Swift name: host(from:)

Retrieves the ReactNativeHost instance that view belongs to.

#### viewWithModuleName:initialProperties:

Swift name: view(moduleName:initialProperties:)

Creates a React root view with the specified module and initial properties.
Parameters:

- moduleName - name of the module to create root view of
- initialProperties - properties passed to the module

Objective-C:

`objc
ReactNativeHost *host = [[ReactNativeHost alloc] initWithConfig:self];
UIView *rootView = [host viewWithModuleName:moduleName
initialProperties:initialProperties];
`

Swift:

`swift
let view = host.view(
moduleName: moduleName,
initialProperties: initialProperties
)
`

$3

RNXHostConfig is a superset of RCTBridgeDelegate and it's backwards
compatible.

#### isDevLoadingViewEnabled

Returns whether the loading view should be visible while loading JavaScript

#### shouldReleaseBridgeWhenBackgrounded

Returns whether the bridge should be released when the app is in the background

#### onFatalError`

Handles a fatal error