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Counter with Conditional Theme - Qwik Typing CST Test
Counter with Conditional Theme — Qwik Code
Changes theme automatically based on whether the count is even or odd.
import { component$, useStore } from '@builder.io/qwik';
export const ConditionalThemeCounter = component$(() => {
const state = useStore({ count: 0 });
const isDark = state.count % 2 === 0;
return (
<div class={isDark ? 'dark-theme' : 'light-theme'}>
<h2>Counter: {state.count}</h2>
<button onClick$={() => state.count++}>+</button>
<button onClick$={() => state.count--}>-</button>
<button onClick$={() => state.count = 0}>Reset</button>
</div>
);
});Qwik Language Guide
Qwik is a next-generation, ultra-fast web framework designed around resumability instead of hydration, enabling instant loading, fine-grained lazy execution, and optimal performance for large-scale interactive applications.
Primary Use Cases
- ▸High-performance websites
- ▸SEO-critical pages
- ▸Large apps with heavy JS footprints
- ▸E-commerce storefronts
- ▸PWAs and edge-rendered apps
Notable Features
- ▸Resumability (no hydration needed)
- ▸Qwik City routing and SSR
- ▸Fine-grained lazy-loading of everything
- ▸Streaming SSR on the edge
- ▸Optimized for Core Web Vitals
Origin & Creator
Created by Miško Hevery (creator of Angular) and developed by Builder.io, officially introduced in 2021.
Industrial Note
Qwik is ideal for ultra-performance-critical sites, marketing pages, e-commerce, dashboards, and massive interactive apps with strict Core Web Vitals budgets.
Quick Explain
- ▸Qwik enables extremely fast websites by skipping hydration entirely and using resumability to continue execution where the server left off.
- ▸It loads JavaScript only when necessary, making even large apps feel instant.
- ▸Qwik is built for performance-first architectures with SSR, edge rendering, Qwik City routing, and component-level lazy loading.
Core Features
- ▸Resumable component architecture
- ▸Server-first rendering
- ▸Event-driven lazy execution
- ▸Filesystem routing via Qwik City
- ▸Zero-JS startup unless needed
Learning Path
- ▸Understand resumability concept
- ▸Learn component$ and QRL patterns
- ▸Use Qwik City for routing
- ▸Master loaders & server actions
- ▸Build & deploy Qwik City app
Practical Examples
- ▸SEO-first marketing site
- ▸E-commerce storefront with instant load
- ▸High-performance interactive dashboard
- ▸Server-rendered content feed
- ▸PWA with minimal JS footprint
Comparisons
- ▸Faster startup than React/Next (hydration-free)
- ▸More performance-oriented than Vue/Nuxt
- ▸More lazy-loaded than Svelte/SvelteKit
- ▸Better for large interactive apps than Astro
- ▸More future-focused than traditional SPA frameworks
Strengths
- ▸Unmatched performance and startup times
- ▸Massive scalability with minimal JS cost
- ▸Great SEO via SSR and streaming
- ▸Excellent DX with Vite tooling
- ▸Automatic code-splitting and lazy loading
Limitations
- ▸Smaller ecosystem compared to React/Vue
- ▸Newer framework with growing community
- ▸Learning curve for the resumability model
- ▸Less plugin/module ecosystem than Next/Nuxt
- ▸Some tooling and library integrations still maturing
When NOT to Use
- ▸Projects needing mature ecosystems
- ▸Legacy React/Vue migration-heavy apps
- ▸Applications requiring many third-party UI libs
- ▸Teams unfamiliar with fine-grained lazy loading
- ▸Small one-off prototypes
Cheat Sheet
- ▸`component$()` - create components
- ▸`useSignal()` - reactive state
- ▸`routeLoader$()` - load server data
- ▸`onClick$=` - lazy event handler
- ▸src/routes - routing entry points
FAQ
- ▸Is Qwik faster than other frameworks?
- ▸Yes - instant load via resumability.
- ▸Does Qwik support SSR?
- ▸Yes, fully via Qwik City.
- ▸Is Qwik stable?
- ▸Yes, production-ready since 2023.
- ▸Does Qwik need hydration?
- ▸No - it uses resumability.
- ▸Does Qwik support TypeScript?
- ▸Yes, first-class TS support.
30-Day Skill Plan
- ▸Week 1: Components, Signals, Directives
- ▸Week 2: Routing + Layouts
- ▸Week 3: SSR + Loaders + Actions
- ▸Week 4: Performance patterns
- ▸Week 5: Edge deployment + advanced patterns
Final Summary
- ▸Qwik is a breakthrough performance-first web framework.
- ▸Its resumability model allows truly instant apps.
- ▸Qwik City provides routing, SSR, data loading, and edge rendering.
- ▸Ideal for SEO, e-commerce, dashboards, and ultra-fast experiences.
- ▸A future-ready paradigm for large-scale web apps.
Project Structure
- ▸src/routes - pages & routing
- ▸src/components - UI components
- ▸src/routes/layout.tsx - layout system
- ▸public/ - static files
- ▸qwik.config.ts - framework config
Monetization
- ▸SaaS platforms
- ▸Ultra-fast landing pages
- ▸E-commerce conversions
- ▸Qwik templates/UI kits
- ▸Performance consulting
Productivity Tips
- ▸Use `$` suffix everywhere required
- ▸Use signals for local reactive state
- ▸Avoid unnecessary client-side logic
- ▸Leverage fine-grained lazy loading
- ▸Optimize SSR via loaders
Basic Concepts
- ▸Resumability vs hydration
- ▸Qwik components & QRLs
- ▸Qwik City routing
- ▸Server and client boundaries
- ▸Lazy-loaded event handlers