#Native Libraries and Autolink

A Lynx native library is an npm package that ships any combination of Elements, Native Modules, and Services for a host Lynx app to consume. Autolink is the integration mechanism that lets the host app discover libraries installed under node_modules and register their capabilities automatically on Android and iOS, instead of wiring each Element, Native Module, or Service by hand.

Autolink currently covers native Android and iOS libraries only. It does not generate Web or HarmonyOS integration code.

#What Is a Lynx Native Library

A library is an npm package that may ship any combination of:

• Elements: custom native UI elements rendered by Lynx, such as <x-button>.
• Native Modules: typed JavaScript-to-native APIs callable from Lynx app code.
• Services: app-wide native singletons that other library capabilities can depend on.

Every library declares its native entry points in a lynx.lib.json manifest at the package root. The three capability types are independent: a library may expose only Elements, only Native Modules, only Services, or any combination of them.

App teams install a library like any other npm dependency. The Android Gradle plugins and the iOS CocoaPods plugin read lynx.lib.json and link the native code into the host app, so the host never needs to know which specific capabilities any given library exposes.

#Consuming a Library

This section is for app teams integrating one or more libraries into a host Lynx app.

#Host App Project Structure

Before enabling Autolink, make sure the host app has a project root that can install npm packages and expose the native app build entry points. A typical host app looks like this:

lynx-app/
├── package.json
├── android/
│   ├── settings.gradle
│   └── app/
│       └── build.gradle
├── ios/
│   └── Podfile
└── src/

• package.json is required so the app can declare Autolink library packages as dependencies.
• For Android, the project needs a Gradle settings file, such as settings.gradle or settings.gradle.kts, and an Android application build file, such as app/build.gradle or app/build.gradle.kts.
• For iOS, the project needs a CocoaPods entry point, usually Podfile. If your team manages Ruby dependencies with Bundler, keep the cocoapods-lynx-library gem in Gemfile.

After you install dependencies, Autolink scans the installed npm packages for lynx.lib.json files at package roots. A lockfile such as package-lock.json, pnpm-lock.yaml, or yarn.lock is recommended for reproducible installs, but it is not required by Autolink.

#Set Up Autolink

Set up Autolink once in the host app. After that, installed library packages can be discovered from node_modules and registered through the generated registry during Lynx initialization.

plugins {
  id 'org.lynxsdk.library-settings'
}

plugins {
  id 'com.android.application'
  id 'org.lynxsdk.library-build'
}

plugin 'cocoapods-lynx-library'

target 'LynxApp' do
  use_lynx_library!
end

#Install a Library

After the app has set up Autolink, install the library package in your Lynx app:

npm install @example/lynx-button

Each library package exposes a lynx.lib.json manifest at the package root. Autolink scans installed npm packages for this file.

{
  "platforms": {
    "android": {
      "packageName": "com.example.button",
      "sourceDir": "android"
    },
    "ios": {
      "sourceDir": "ios",
      "podspecPath": "ios/build.podspec"
    }
  }
}

For Android, platforms.android.packageName is required, and sourceDir defaults to android. For iOS, sourceDir defaults to ios, and podspecPath defaults to the first .podspec found under the iOS source directory.

After installing or updating a library package, sync/build the Android app and run pod install for iOS so the generated registry and native dependencies are refreshed. You do not need to add per-library manual registration code in the app.

#Authoring a Library

This section is for library authors building a reusable native package for other Lynx apps to install.

#Library Package Structure

A typical library package looks like this:

lynx-button/
├── package.json
├── lynx.lib.json
├── types/
│   └── index.d.ts
├── src/
│   └── index.ts
├── generated/
│   └── ButtonModule.ts
├── android/
│   └── src/main/java/com/example/button/
│       ├── ButtonElement.java
│       ├── ButtonModule.java
│       ├── ButtonService.java
│       └── generated/ButtonModuleSpec.java
├── ios/
│   ├── build.podspec
│   └── src/
│       ├── ButtonElement.m
│       ├── ButtonModule.m
│       ├── ButtonService.m
│       └── generated/
│           ├── ButtonModuleSpec.h
│           └── ButtonModuleSpec.m
└── example/

• package.json makes the package installable from npm and usually provides the codegen script.
• lynx.lib.json is the Autolink contract. It tells the host app where Android and iOS source code lives.
• types/index.d.ts describes typed Native Module APIs, if the library exposes any. Codegen uses these declarations to create platform specs and the JavaScript facade.
• src/index.ts exports the JavaScript API that app code imports.
• android/ and ios/ contain native implementations and generated native specs.
• example/ is a local app used by the library author to verify the package.

#Create a Library

Create a new library package interactively:

npm create lynx-library

For scripts and tests, the same scaffold can run without prompts:

npm create lynx-library -- \
  --dir ./lynx-button \
  --types native-module,element,service \
  --package-name @example/lynx-button \
  --android-package com.example.button \
  --module-name ButtonModule \
  --element-name x-button \
  --service-name ButtonService

The generated package includes:

• package.json with "codegen": "lynx-autolink-codegen"
• lynx.lib.json for Android and iOS Autolink discovery
• types/index.d.ts for typed Native Module declarations, when the library exposes Native Modules
• src/index.ts for the JavaScript facade
• android/ and ios/ native source folders
• example/, tsconfig.json, and README.md

Run codegen from the library root:

npm run codegen

lynx-autolink-codegen reads lynx.lib.json. For Native Modules, it scans types/**/*.d.ts for @lynxmodule declarations:

/** @lynxmodule */
export declare class ButtonModule {
  getLabel(id: string): string;
  setEnabled(id: string, enabled: boolean): void;
}

It generates:

• generated/<ModuleName>.ts for the JavaScript facade
• Android <ModuleName>Spec.java
• iOS <ModuleName>Spec.h and <ModuleName>Spec.m

The first version supports void, string, number, boolean, and nullable unions with null.

#Write Native APIs

Autolink exposes the LynxAutolink* annotations and markers as the public authoring API for Lynx libraries. Native Modules usually extend the spec generated by lynx-autolink-codegen; Elements and Services are discovered from their native markers.

package com.example.button;

import com.example.button.generated.ButtonModuleSpec;
import com.lynx.jsbridge.LynxAutolinkNativeModule;
import com.lynx.jsbridge.LynxMethod;
import com.lynx.tasm.behavior.LynxContext;
import java.util.HashMap;
import java.util.Map;

@LynxAutolinkNativeModule(name = "ButtonModule")
public final class ButtonModule extends ButtonModuleSpec {
  private final Map<String, Boolean> enabledState = new HashMap<>();

  public ButtonModule(LynxContext context) {
    super(context);
  }

  @Override
  @LynxMethod
  public String getLabel(String id) {
    return "Button " + id;
  }

  @Override
  @LynxMethod
  public void setEnabled(String id, boolean enabled) {
    enabledState.put(id, enabled);
  }
}

package com.example.button;

import android.content.Context;
import android.view.Gravity;
import android.widget.TextView;
import com.lynx.tasm.behavior.LynxAutolinkElement;
import com.lynx.tasm.behavior.LynxContext;
import com.lynx.tasm.behavior.LynxProp;
import com.lynx.tasm.behavior.ui.LynxUI;

@LynxAutolinkElement(name = "x-button")
public final class ButtonElement extends LynxUI<TextView> {
  public ButtonElement(LynxContext context) {
    super(context);
  }

  @Override
  protected TextView createView(Context context) {
    TextView view = new TextView(context);
    view.setGravity(Gravity.CENTER);
    view.setText("x-button");
    return view;
  }

  @LynxProp(name = "text")
  public void setText(String text) {
    mView.setText(text == null ? "" : text);
  }
}

package com.example.button;

import android.content.Context;
import com.lynx.tasm.service.IServiceProvider;
import com.lynx.tasm.service.LynxAutolinkService;

@LynxAutolinkService
public final class ButtonService implements IServiceProvider {
  private Context appContext;

  @Override
  public Class<? extends IServiceProvider> getServiceClass() {
    return ButtonService.class;
  }

  @Override
  public void onInitialize(Context context) {
    appContext = context.getApplicationContext();
  }

  public void recordClick(String id) {
    // Send analytics or call platform capabilities here.
  }
}

// ButtonModule.h
#import <Foundation/Foundation.h>
#import <Lynx/LynxModule.h>
#import "generated/ButtonModuleSpec.h"

NS_ASSUME_NONNULL_BEGIN

@LynxAutolinkNativeModule("ButtonModule")
@interface ButtonModule : NSObject <ButtonModuleSpec>

@end

NS_ASSUME_NONNULL_END

// ButtonModule.m
#import "ButtonModule.h"

@implementation ButtonModule {
  NSMutableDictionary<NSString *, NSNumber *> *_enabledState;
}

- (instancetype)init {
  self = [super init];
  if (self) {
    _enabledState = [NSMutableDictionary dictionary];
  }
  return self;
}

- (NSString *)getLabel:(NSString *)buttonId {
  return [NSString stringWithFormat:@"Button %@", buttonId];
}

- (void)setEnabled:(NSString *)buttonId enabled:(BOOL)enabled {
  _enabledState[buttonId] = @(enabled);
}

@end

// ButtonElement.h
#import <UIKit/UIKit.h>
#import <Lynx/LynxUI.h>

NS_ASSUME_NONNULL_BEGIN

@interface ButtonElement : LynxUI<UILabel *>

@end

NS_ASSUME_NONNULL_END

// ButtonElement.m
#import "ButtonElement.h"
#import <Lynx/LynxPropsProcessor.h>

@LynxAutolinkUI("x-button")
@implementation ButtonElement

LYNX_PROP_SETTER("text", setText, NSString *) {
  self.view.text = value ?: @"";
}

- (UILabel *)createView {
  UILabel *label = [[UILabel alloc] init];
  label.textAlignment = NSTextAlignmentCenter;
  label.text = @"x-button";
  return label;
}

@end

// ButtonService.h
#import <Foundation/Foundation.h>
#import <LynxServiceAPI/ServiceAPI.h>

NS_ASSUME_NONNULL_BEGIN

@protocol ButtonServiceProtocol <LynxServiceProtocol>

- (void)recordClick:(NSString *)buttonId;

@end

@interface ButtonService : NSObject <ButtonServiceProtocol>

@end

NS_ASSUME_NONNULL_END

// ButtonService.m
#import "ButtonService.h"

@LynxAutolinkService(ButtonService, ButtonServiceProtocol)
@implementation ButtonService

+ (instancetype)sharedInstance {
  static ButtonService *service;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    service = [[ButtonService alloc] init];
  });
  return service;
}

- (void)recordClick:(NSString *)buttonId {
  // Send analytics or call platform capabilities here.
}

@end

For iOS packages that already use Lynx native registration macros, Autolink also scans existing LYNX_LAZY_REGISTER_UI, LYNX_LAZY_REGISTER_SHADOW_NODE, and @LynxServiceRegister(...) declarations, so those packages can be linked without rewriting their native code.

#Distribute a Library

Publish the library like any other npm package: pick a name, often scoped as @example/lynx-button, set a version in package.json, and run npm publish. App teams add the published version to their package.json and Autolink picks the library up the next time they install dependencies. Pin a compatible Lynx SDK version range in the library's peerDependencies so app teams get a clear signal when the library and the host SDK drift apart.

#How Autolink Works

Autolink runs at build time. It scans every npm package under node_modules for a lynx.lib.json manifest, then generates a per-app registry that lists every Element, Native Module, and Service the installed libraries expose. Android registry generation runs through the Gradle settings and build plugins; iOS registry generation runs through the CocoaPods plugin and emits a registry pod. The host app loads the generated registry once during LynxEnv initialization, which is why no per-library wiring code lives in the host.