Jepsh – A Next-Generation Universal Framework

Performance by Default • Simplified State Management • True Cross-Platform Consistency

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1. Guiding Principles

Principle	How Jepsh Lives It
Performance by Default	Every API ships with a zero-cost abstraction and an opt-in progressive enhancement layer.
Simplified State Management	One mental model—Signal → View → Reaction—works the same on Web, Android, iOS.
True Cross-Platform Consistency	Pixel-perfect rendering via Jepsh Render Kernel + Adaptive Shells that respect each OS.

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2. Architecture at 10,000 ft

graph TD
    A["Declarative UI (JXL)"] --> B("Jepsh Render Kernel")
    B --> C{"Adaptive Shell"}
    C --> D["Web DOM / Canvas"]
    C --> E["Android View / Compose"]
    C --> F["iOS UIView / SwiftUI"]
    G["Reactive Store (Atom)"] --> A
    H["Native Bridge (FFI)"] --> C

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3. Language & Tooling Stack

Target	Language	Compiler	Tooling
Web	TypeScript → WASM + JS	jepsh-webc	VS Code extension, Chrome DevTools plugin
Android	Kotlin (JVM)	jepsh-androidc	AS plugin, Compose preview
iOS	Swift	jepsh-iosc	Xcode template + live canvas

Write once in JXL (Jepsh eXtensible Language) – a strict subset of TS/Kotlin/Swift that compiles to each host language.

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4. Performance by Default

4.1 Compile-Time Optimizations

• Tree-Shaking of Runtime: Unused reactivity & layout code stripped at compile time.
• Layout Pre-Calculation: Static parts pre-computed; only dynamic regions diff.
• Binary Splitting: WASM bundles < 50 KB for initial render; rest streamed.

4.2 Runtime Optimizations

• Frame-Budget Scheduler – 60 FPS guarantee via micro-task batching.
• Zero-Copy Memory – Large assets (images, video) mapped directly from disk or GPU.
• Off-Main-Thread Rendering – Web Workers on web; Kotlin coroutines on Android; Swift Concurrency on iOS.

// JXL example – no extra annotations, auto-optimized
view Counter {
  signal count: Int = 0
  render {
    Button("Clicked \(count) times") {
      count += 1
    }
  }
}

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5. Simplified State Management

5.1 The Atom Pattern

A single reactive primitive Atom<T> everywhere:

atom user: User? = nil
atom theme: Theme = .system

• No Context, Provider, or Services—just atoms.
• Smart re-renders via structural diffs (à-la VDOM but 4× lighter).
• Built-in persistence layer (@Persist) for offline & multi-device sync.

5.2 DevTools

• Time-travel debugger across Web, Android, iOS.
• State heat-map shows which atoms trigger re-renders in real time.

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6. True Cross-Platform Consistency

6.1 Adaptive Shells

Each platform gets a thin Shell that:

• Applies OS-specific motion curves & haptics.
• Respects accessibility & dark-mode settings.
• Provides native navigation gestures (iOS swipe-back, Android back-button).

6.2 Design Tokens → Native Widgets

Use Jepsh Tokens → auto-maps to:

• Material You (Android)
• Human Interface Guidelines (iOS)
• CSS Variables (Web)

# tokens.yml
color.primary: '#3B82F6'
radius.card: 12
motion.duration: 200ms

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7. Tooling & DX

7.1 Unified CLI

npm i -g jepsh
jepsh create myApp
jepsh dev --platform=all      # spins up Web, Android, iOS emulators
jepsh build --target=prod

7.2 Hot-Reload Across Stack

• Web: HMR via WebSockets
• Android: Live edit via AS plugin
• iOS: SwiftUI-style preview diffing

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8. Security by Blueprint

Threat	Jepsh Mitigation
XSS	JXL escapes by default; no innerHTML.
CSRF	Auto-generated double-submit tokens on forms.
Memory Leaks	Composables/Views auto-dispose via DisposableEffect equivalent.
Secrets	Compile-time env injection; never bundled.

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9. Migration Path

From	Strategy
React / Angular / Vue	jepsh migrate --from=react auto-wraps components.
Flutter / React Native	Gradual module replacement via Jepsh Module Bridge.
Native SwiftUI / Jetpack Compose	Use Jepsh Shell inside existing apps.

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10. Roadmap

Phase	Milestone	ETA
α	Web (WASM)	Q4 2025
β	Android & iOS shells, CLI tooling	Q2 2026
GA	Marketplace, VS Code + Xcode + AS plugins	Q4 2026
v2	Server-driven UI, edge rendering	2027

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11. Try Jepsh Today

npx jepsh@next create helloJepsh
cd helloJepsh
jepsh dev

helloJepsh launches simultaneously in your browser, Android Studio, and Xcode simulator—identical pixels, 60 FPS, zero config.

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Jepsh is Apache 2.0 licensed, community-driven, and accepting RFCs at github.com/jepsh/rfc.