2nd/10_Wiki/Topics/Frontend/Fabric.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-fabric	Fabric	10_Wiki/Topics	verified	self	React Native Fabric Fabric Renderer RN New Architecture	none	A	0.9	applied	react-native fabric renderer mobile jsi		2026-05-10	pending	language framework cpp react-native

Fabric

매 한 줄

"매 Fabric 는 React Native 의 new renderer — JSI 기반 synchronous JS↔native 의 enables". 2018-2024 에 incrementally rolled out, RN 0.74+ 에서 default. 매 legacy bridge (async JSON serialization) 의 replace, 매 concurrent React features (Suspense, Transitions) 의 mobile 의 enable.

매 핵심

매 Architecture (vs Old Bridge)

• Old bridge: JS thread ↔ Native thread async JSON messages. Serialize cost, no sync calls, list jank.
• Fabric: JSI (JavaScript Interface) — JS engine (Hermes) 의 C++ HostObjects 의 direct access. Sync calls, shared memory, type-safe via codegen.

매 Components

• JSI: lightweight C++ API for JS engines (Hermes/JSC). 매 binding의 base.
• Fabric Renderer (C++): shadow tree, layout (Yoga), commit phase. 매 cross-platform.
• TurboModules: lazy-loaded native modules with codegen-typed interface.
• Codegen: TS/Flow types → C++/Java/ObjC native code.
• Hermes: default JS engine (faster startup, lower memory, bytecode).

매 응용

1. React 18 concurrent features (Suspense, useTransition) on mobile.
2. Synchronous measure/layout queries.
3. Type-safe native module bindings.
4. New Architecture only libs (Reanimated 3, Skia).

💻 패턴

Enable New Architecture (RN 0.76+)

# Default ON in 0.76+; explicit:
# ios/Podfile
# RCT_NEW_ARCH_ENABLED=1 bundle exec pod install

# android/gradle.properties
newArchEnabled=true

Spec-driven Native Component (Codegen)

// MyViewNativeComponent.ts
import type { ViewProps } from 'react-native';
import type { Int32, WithDefault } from 'react-native/Libraries/Types/CodegenTypes';
import codegenNativeComponent from 'react-native/Libraries/Utilities/codegenNativeComponent';

export interface NativeProps extends ViewProps {
  color?: string;
  count?: WithDefault<Int32, 0>;
}

export default codegenNativeComponent<NativeProps>('MyView');

TurboModule Spec

// NativeCalculator.ts
import type { TurboModule } from 'react-native';
import { TurboModuleRegistry } from 'react-native';

export interface Spec extends TurboModule {
  add(a: number, b: number): number;       // SYNC call (impossible on old bridge)
  greet(name: string): Promise<string>;
}

export default TurboModuleRegistry.getEnforcing<Spec>('Calculator');

iOS TurboModule Implementation

// Calculator.mm
#import "Calculator.h"

@implementation Calculator
RCT_EXPORT_MODULE()

- (NSNumber *)add:(double)a b:(double)b {
  return @(a + b);
}

- (std::shared_ptr<facebook::react::TurboModule>)
   getTurboModule:(const facebook::react::ObjCTurboModule::InitParams &)params {
  return std::make_shared<facebook::react::NativeCalculatorSpecJSI>(params);
}
@end

JSI Direct Binding (advanced)

// C++ side
runtime.global().setProperty(
  runtime, "nativeAdd",
  Function::createFromHostFunction(runtime,
    PropNameID::forAscii(runtime, "nativeAdd"), 2,
    [](Runtime& rt, const Value&, const Value* args, size_t) {
      return Value(args[0].asNumber() + args[1].asNumber());
    }));

Concurrent Features on RN

import { useTransition, Suspense } from 'react';

function App() {
  const [isPending, startTransition] = useTransition();
  const [query, setQuery] = useState('');
  return (
    <>
      <TextInput onChangeText={(t) => startTransition(() => setQuery(t))} />
      <Suspense fallback={<Spinner />}>
        <Results query={query} />
      </Suspense>
    </>
  );
}

매 결정 기준

상황	Approach
New project (2026)	Fabric default (RN 0.76+)
Legacy app	Migrate incrementally; interop layer
Custom native view	Fabric component + codegen
Sync native call	TurboModule (impossible old)
Heavy animation	Reanimated 3 (Fabric-only)

기본값: New Architecture ON, Hermes ON, codegen-driven specs.

🔗 Graph

• 부모: React Native · React
• 변형: TurboModules · Hermes · JSI
• 응용: Reanimated · React Native Skia
• Adjacent: Yoga Layout · Bridge (Legacy) · Concurrent React

🤖 LLM 활용

언제: RN new architecture migration, TurboModule/Fabric component authoring, JSI binding. 언제 X: pure JS-only RN questions (state management, navigation library).

❌ 안티패턴

• Mixing old bridge modules with Fabric without interop: runtime crash.
• Skipping codegen: hand-written specs drift from native; codegen 의 source of truth.
• JSI HostObject 의 long-running work: blocks JS thread; offload to native thread.
• Old NativeModules.X API in new code: TurboModuleRegistry 의 사용.

🧪 검증 / 중복

• Verified (React Native official docs — New Architecture, RFC 0588 Fabric).
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — Fabric renderer / new arch full content