React Native Navigation Codebase

Architecture Overview

RNN has three layers that mirror each other:

JS/TS (src/)  →  TurboModule bridge  →  iOS native (ios/)
                                     →  Android native (android/)

A navigation command (e.g. push) flows:

Navigation.push() → Commands.ts → processing pipeline → NativeCommandsSender.ts
TurboModule: RNNTurboModule (iOS) / NavigationTurboModule.kt (Android)
iOS: RNNCommandsHandler → RNNViewControllerFactory → UIKit controllers
Android: Navigator → LayoutFactory → View-based controllers (no Fragments)

Read ARCHITECTURE.md for the full overview.

Key Cross-Layer Mappings

Layout Types → Native Controllers

JS Layout Type	iOS Controller	Android Controller
`component`	`RNNComponentViewController`	`ComponentViewController`
`stack`	`RNNStackController` (UINavigationController)	`StackController`
`bottomTabs`	`RNNBottomTabsController` (UITabBarController)	`BottomTabsController`
`sideMenu`	`RNNSideMenuViewController` (MMDrawerController)	`SideMenuController` (DrawerLayout)
`topTabs`	`RNNTopTabsViewController`	`TopTabsController` (ViewPager)
`splitView`	`RNNSplitViewController`	N/A (iOS only)
`externalComponent`	`RNNExternalViewController`	`ExternalComponentViewController`

Options → Presenters

Each controller type has a Presenter that applies options to views:

iOS Controller	iOS Presenter	Android Presenter
`RNNComponentViewController`	`RNNComponentPresenter`	`ComponentPresenter`
`RNNStackController`	`RNNStackPresenter` + `TopBarPresenter`	`StackPresenter`
`RNNBottomTabsController`	`RNNBottomTabsPresenter`	`BottomTabsPresenter`
`RNNSideMenuViewController`	`RNNSideMenuPresenter`	`SideMenuPresenter`

Events (same names both platforms)

Event	Trigger
`RNN.ComponentDidAppear`	Screen becomes visible
`RNN.ComponentDidDisappear`	Screen hidden
`RNN.NavigationButtonPressed`	TopBar button tap
`RNN.BottomTabSelected`	Tab changed
`RNN.ModalDismissed`	Modal dismissed
`RNN.ScreenPopped`	Screen popped from stack
`RNN.CommandCompleted`	Any command finished

Where to Find Things

By task: "I need to fix/change X"

Task	JS File(s)	iOS File(s)	Android File(s)
Command execution	`src/commands/Commands.ts`	`ios/RNNCommandsHandler.mm`	`react/NavigationTurboModule.kt`
Layout creation	`src/commands/LayoutTreeParser.ts`	`ios/RNNViewControllerFactory.mm`	`options/LayoutFactory.java`
Options processing	`src/commands/OptionsProcessor.ts`	`ios/RNNNavigationOptions.mm`	`options/Options.java`
Options application	—	`ios/*Presenter.mm`	`viewcontrollers/*Presenter.java`
TopBar	`src/interfaces/Options.ts` (TopBarOptions)	`ios/TopBarPresenter.mm`, `ios/RNNUIBarButtonItem.mm`	`views/stack/topbar/`
Bottom tabs	`src/interfaces/Options.ts` (BottomTabsOptions)	`ios/RNNBottomTabsPresenter.mm`	`viewcontrollers/bottomtabs/`
Modals	`src/commands/Commands.ts`	`ios/RNNModalManager.mm`	`viewcontrollers/modal/ModalStack.java`
Overlays	`src/commands/Commands.ts`	`ios/RNNOverlayManager.mm`	`viewcontrollers/overlay/OverlayManager.kt`
Animations	`src/interfaces/Options.ts` (AnimationOptions)	`ios/ScreenAnimationController.mm`	`viewcontrollers/stack/StackAnimator.kt`
React view rendering	—	`ios/RNNReactView.mm`	`react/ReactView.java`
Events to JS	`src/adapters/NativeEventsReceiver.ts`	`ios/RNNEventEmitter.mm`	`react/events/EventEmitter.java`
Component registration	`src/components/ComponentRegistry.ts`	—	—

By directory

src/ — JS public API, commands, processing pipeline. See src/ARCHITECTURE.md
ios/ — All Obj-C/C++ native code. See ios/ARCHITECTURE.md
ios/TurboModules/ — New architecture entry points (RNNTurboModule, RNNTurboManager, RNNTurboCommandsHandler)
android/src/main/java/com/reactnativenavigation/ — All Java/Kotlin native code. See android/ARCHITECTURE.md
playground/ — Demo app for development and E2E tests
playground/src/screens/ — Test screens exercising every feature
playground/e2e/ — Detox E2E tests

Options Resolution Order

Options are applied in ascending priority:

Default options (from Navigation.setDefaultOptions()) — lowest priority
Static options (from component class or Navigation.registerComponent)
Options passed in the layout call (e.g. push, setRoot)
mergeOptions() — runtime override, highest priority

JS Processing Pipeline (exact order)

API layout → OptionsCrawler.crawl() → LayoutProcessor.process()
  → LayoutTreeParser.parse() → LayoutTreeCrawler.crawl()
  → OptionsProcessor (colors, assets, custom) → NativeCommandsSender

iOS Patterns

All controllers conform to RNNLayoutProtocol
RNNBasePresenter subclasses apply options — applyOptionsOnInit:, applyOptions:, mergeOptions:resolvedOptions:
Commands run on main thread (RCTExecuteOnMainQueue)
React views: RNNReactView wraps RCTSurfaceHostingView (new arch)
Overlays use separate UIWindow instances (RNNOverlayWindow)
RNNReactComponentRegistry caches React component instances

Android Patterns

View-based, NOT Fragment-based
All commands dispatched via UiThread.post()
ViewController<T extends ViewGroup> is the base — createView() is abstract
ParentController extends ChildController extends ViewController
Bottom tabs use AHBottomNavigation library
Three root layouts in NavigationActivity: rootLayout, modalsLayout, overlaysLayout
Tab attachment modes: Together, OnSwitchToTab, AfterInitialTab

Development Workflow

Playground app

yarn start — Metro bundler
yarn xcode — Open iOS project
yarn studio — Open Android project
yarn pod-install — Install iOS pods

Testing

yarn test-js — Jest unit tests
yarn test-unit-ios — iOS native unit tests (XCTest)
yarn test-unit-android — Android native unit tests (JUnit + Robolectric)
yarn test-e2e-ios-ci / yarn test-e2e-android-ci — Detox E2E tests

Building

yarn prepare — Builds src/ → lib/ (ESM + types)
Codegen config: rnnavigation in package.json

Common Gotchas

iOS uses UIKit subclasses (UINavigationController, UITabBarController); Android uses custom View hierarchy
splitView is iOS-only
Side menu: iOS uses MMDrawerController (3rd party); Android uses DrawerLayout (native)
Options that exist in JS types may not be implemented on both platforms — check the presenter
passProps are stored in JS Store, not sent to native (cleared before bridge crossing)
The lib/ folder is generated — never edit it, edit src/ instead

rnn-codebase