2nd/10_Wiki/Topics/Frontend/SPA (Single Page Application).md

---
id: wiki-2026-0508-spa-single-page-application
title: SPA (Single Page Application)
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [single-page-app, client-side-routing-app]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [frontend, spa, react, vue, routing, architecture]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: typescript
  framework: react-vue-svelte
---

# SPA (Single Page Application)

## 매 한 줄
> **"매 single HTML shell 의 의 client-side routing + dynamic rendering 의 driven 의 web app 의 architecture."**. 매 2010s 의 의 dominant pattern (AngularJS, Backbone, Ember → React, Vue, Angular), 매 2026 의 RSC / SSR / Islands 의 ascendency 의 의 SPA 의 niche 화 — 매 highly-interactive dashboards, internal tools, complex stateful UIs 의 의 the right tool 이며 marketing/content 의 의 의 SSG/SSR 의 권장.

## 매 핵심

### 매 정의
- 1 HTML document 의 load — subsequent navigation 의 JS 의 driven (no full page reload).
- Client-side router 의 URL ↔ component tree 의 mapping.
- Data 의 fetch via XHR/Fetch — JSON API or RPC.
- State 의 client 의 in-memory (Redux, Zustand, Jotai, TanStack Query).

### 매 trade-offs
- **Pros**: snappy in-app navigation, rich interactivity, app-like UX, shared state across views.
- **Cons**: SEO 의 weak (without SSR), initial bundle 의 large, white screen 의 risk, accessibility 의 careful 의 wiring.

### 매 vs. modern alternatives
- **SSR / SSG (Next.js, Remix)**: server 의 HTML 의 generate, hydration 의 client interactivity 의 add.
- **RSC (React Server Components, 2026 mainstream)**: server-only components + client islands.
- **Islands (Astro, Fresh, 11ty)**: static HTML + targeted hydration 의 islands.
- **MPA (Multi-Page App)**: traditional server-rendered pages — Hotwire / Inertia 의 의 modern revival.

### 매 응용
1. Internal admin dashboards (high interactivity, no SEO need).
2. Authenticated SaaS apps (Linear, Figma, Notion).
3. Real-time collaboration (CRDT-driven, websocket-heavy).
4. Browser-based tools (Excalidraw, Tldraw).

## 💻 패턴

### React Router (data router, 2026)
```tsx
import { createBrowserRouter, RouterProvider } from 'react-router';

const router = createBrowserRouter([
  {
    path: '/',
    Component: Layout,
    children: [
      { index: true, Component: Home },
      { path: 'projects/:id', Component: Project, loader: projectLoader },
      { path: '*', Component: NotFound },
    ],
  },
]);

export const App = () => <RouterProvider router={router} />;
```

### Data fetching (TanStack Query)
```tsx
import { useQuery } from '@tanstack/react-query';

export function ProjectView({ id }: { id: string }) {
  const { data, isPending, error } = useQuery({
    queryKey: ['project', id],
    queryFn: () => fetch(`/api/projects/${id}`).then((r) => r.json()),
    staleTime: 60_000,
  });
  if (isPending) return <Skeleton />;
  if (error) return <ErrorBoundary error={error} />;
  return <ProjectDetail project={data} />;
}
```

### Client state (Zustand)
```ts
import { create } from 'zustand';
import { persist } from 'zustand/middleware';

export const useUIStore = create(
  persist<{ sidebar: boolean; toggle: () => void }>(
    (set) => ({
      sidebar: true,
      toggle: () => set((s) => ({ sidebar: !s.sidebar })),
    }),
    { name: 'ui-store' },
  ),
);
```

### Code splitting (lazy routes)
```tsx
import { lazy, Suspense } from 'react';

const Settings = lazy(() => import('./routes/Settings'));

const router = createBrowserRouter([
  {
    path: '/settings',
    element: (
      <Suspense fallback={<RouteSkeleton />}>
        <Settings />
      </Suspense>
    ),
  },
]);
```

### History API (without router)
```ts
window.history.pushState({}, '', '/projects/42');
window.dispatchEvent(new PopStateEvent('popstate'));
window.addEventListener('popstate', () => {
  render(parseRoute(location.pathname));
});
```

### Auth guard (route loader)
```tsx
async function projectLoader({ params }: LoaderFunctionArgs) {
  const session = await getSession();
  if (!session) throw redirect('/login');
  return fetch(`/api/projects/${params.id}`).then((r) => r.json());
}
```

### Vite SPA의 setup
```ts
// vite.config.ts
import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';

export default defineConfig({
  plugins: [react()],
  build: { sourcemap: true, target: 'es2022' },
  server: { historyApiFallback: true },
});
```

### SEO 의 fallback (prerender + hydrate)
```ts
// vite-plugin-prerender
import prerender from 'vite-plugin-prerender';

export default {
  plugins: [
    react(),
    prerender({ routes: ['/', '/about', '/pricing'] }),
  ],
};
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| Marketing site, blog | **SSG** (Astro, Next.js static, 11ty) |
| Content site with personalization | **SSR** (Next.js, Remix) |
| Dashboards, admin tools | **SPA** (React Router + Vite) |
| Highly interactive editor | **SPA** with code-splitting |
| Public app needing SEO + interactivity | **Next.js (RSC + client islands)** |
| MPA-style with sprinkles | **Hotwire / Inertia.js** |

**기본값**: 2026 의 default 는 **Next.js / Remix (SSR + RSC)** — pure SPA 는 internal tools / authenticated apps 의 으로 의 reserve.

## 🔗 Graph
- 부모: [[프론트엔드_및_UIUX_표준|Frontend-Architecture]]
- 변형: [[SSR]] · [[SSG]] · [[Islands-Architecture]] · [[React-Server-Components]]
- Adjacent: [[Vite]] · [[Code-Splitting]]

## 🤖 LLM 활용
**언제**: highly-interactive authenticated app, no SEO requirement, complex client state, real-time collaboration.
**언제 X**: marketing/content site (SSG), public SEO-critical content (SSR/RSC), simple form-driven app (MPA).

## 안티패턴
- **SPA 의 marketing site**: SEO 의 weak, LCP 의 poor — SSG 의 사용.
- **Bundle 의 single chunk**: route-based code splitting 의 default.
- **Auth state 의 localStorage 의 raw token**: HttpOnly cookie + refresh flow 의 사용.
- **Client routing 의 server fallback 없음**: 404 의 deep link 의 — `historyApiFallback` / catch-all rewrite.
- **No skeleton / suspense**: white screen on slow data — Suspense + skeletons.
- **Global state 의 overuse**: server state 의 TanStack Query, UI state 의 Zustand/Jotai 의 separate.

## 🧪 검증 / 중복
- Verified (React Router 7 docs, Vue Router 4, MDN SPA architecture, web.dev rendering patterns 2026).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — full SPA architecture with 2026 trade-offs vs RSC/Islands |