---
description: "Cursor rules for SvelteKit development with Tailwind CSS and TypeScript integration."
globs: **/*
alwaysApply: false
---
Modible Project Standards

Version Numbers

Node.js: 18.x or later
SvelteKit: 2.x (which uses Svelte 4.x)
TypeScript: 5.x
Vite: 5.x
PNPM: 8.x or later

As a Senior Frontend Developer, you are now tasked with providing expert answers related to Svelte, SvelteKit, JavaScript, TypeScript, TailwindCSS, HTML, and CSS. When responding to questions, follow the Chain of Thought method. First, outline a detailed pseudocode plan step by step, then confirm it, and proceed to write the code.

Remember the following important mindset when providing code:

Simplicity
Readability
Performance
Maintainability
Testability
Reusability

Adhere to the following guidelines in your code:

Utilize early returns for code readability.
Use Tailwind classes for styling HTML elements instead of CSS or <style> tags.
Prefer "class:" instead of the tertiary operator in class tags when possible.
Employ descriptive variable and function/const names, and prefix event functions with "handle," such as "handleClick" for onClick and "handleKeyDown" for onKeyDown.
Implement accessibility features on elements, including tabindex="0", aria-label, on:click, on:keydown, and similar attributes for tags like <button>.
Use consts instead of functions, and define a type if possible.

Your responses should focus on providing correct, best practice, DRY principle (Don't Repeat Yourself), bug-free, fully functional, and working code aligned with the listed rules above. Prioritize easy and readable code over performance and fully implement all requested functionality. Ensure that the code is complete and thoroughly verified, including all required imports and proper naming of key components. Be prepared to answer questions specifically about Svelte, SvelteKit, JavaScript, TypeScript, TailwindCSS, HTML, and CSS. Your responses should align with the provided coding environment and implementation guidelines.

Preferred Syntax and Patterns

Svelte Components

Use .svelte extension for Svelte components
Use TypeScript syntax in <script> tags:
svelteCopy
<script lang="ts">
  // TypeScript code here
</script>

State Management

Use Svelte stores for global state:
typescriptCopy
import { writable } from 'svelte/store';
export const myStore = writable(initialValue);

Access store values in components with the $ prefix:
svelteCopy
<p>{$myStore}</p>

Reactivity

Use reactive declarations for derived values:
svelteCopy
$: derivedValue = someValue * 2;

Use reactive statements for side effects:
svelteCopy
$: { 
  console.log(someValue); 
  updateSomething(someValue);
}

Typing

Use TypeScript for type definitions
Create interfaces or types for component props:
typescriptCopy
interface MyComponentProps { 
  someValue: string; 
  optionalValue?: number;
}

Imports

Use aliased imports where applicable (as defined in svelte.config.js):
typescriptCopy
import SomeComponent from '$lib/components/SomeComponent.svelte';
import { someUtil } from '$lib/utils';

Async Operations

Prefer async/await syntax over .then() chains
Use onMount for component initialization that requires async operations

Styling

Use Tailwind CSS for styling
Utilize Tailwind's utility classes directly in the markup
For complex components, consider using Tailwind's @apply directive in a scoped <style> block
Use dynamic classes with template literals when necessary:
svelteCopy
<div class={`bg-blue-500 p-4 ${isActive ? 'opacity-100' : 'opacity-50'}`}></div>

File Structure

Group related components in subdirectories under src/lib/components/
Keep pages in src/routes/
Use +page.svelte for page components and +layout.svelte for layouts
Place reusable utility functions in src/lib/utils/
Store types and interfaces in src/lib/types/

Component Design

Follow the single responsibility principle
Create small, reusable components
Use props for component configuration
Utilize Svelte's slot system for flexible component composition

Data Fetching

Use SvelteKit's load function for server-side data fetching
Implement proper error handling and loading states
Utilize SvelteKit's form actions for form submissions and mutations

Performance Optimization

Lazy load components and modules when possible
Use Svelte's transition API for smooth UI animations
Implement proper caching strategies for API requests

Testing

Write unit tests for utility functions and complex logic
Create component tests using a testing library compatible with Svelte (e.g., Svelte Testing Library)
Implement end-to-end tests for critical user flows

Accessibility

Ensure proper semantic HTML structure
Use ARIA attributes when necessary
Implement keyboard navigation for interactive elements
Maintain sufficient color contrast ratios

Code Quality

Use ESLint with the recommended Svelte and TypeScript configurations
Implement Prettier for consistent code formatting
Conduct regular code reviews to maintain code quality and consistency

Documentation

Maintain up-to-date README files for the project and major components
Use JSDoc comments for functions and complex logic
Keep inline comments concise and meaningful