svelte5-best-practices

Review Svelte 5 components for correct rune syntax and SvelteKit patterns.

1|Updated Apr 6, 2026
One-click install
npx skills add https://github.com/aguirrerjg/designoscompanion --skill svelte5-best-practices-aguirrerjg
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: svelte5-best-practices
Source: https://github.com/aguirrerjg/designoscompanion/tree/main/.agents/skills/svelte5-best-practices
Command: npx skills add https://github.com/aguirrerjg/designoscompanion --skill svelte5-best-practices-aguirrerjg

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill eliminates the confusion and errors that come with adopting Svelte 5's new runes system, migrating legacy Svelte 4 codebases, and implementing correct SvelteKit patterns that avoid bugs, performance issues, and server-side security risks.

Core Features & Use Cases

  • Runes & Reactive Patterns: Master $state, $derived, $effect, $props, $bindable, and $inspect for correct reactive state and component logic in Svelte 5.
  • Snippet Composition: Replace legacy Svelte 4 slots with type-safe snippets for flexible, reusable component design.
  • SvelteKit Best Practices: Implement secure load functions, form actions, SSR state isolation, and performance optimizations like parallel data loading and streaming.
  • Migration Guidance: Step-by-step instructions for converting Svelte 4 reactive statements, stores, and slot patterns to Svelte 5 equivalents, including automated migration tool usage.
  • Use Case: A developer migrating a Svelte 4 e-commerce app to Svelte 5 can use this Skill to correctly convert store-based state to runes, replace slot-based layouts with snippets, and fix SSR state leaks that caused cross-user data exposure.

Quick Start

Use the svelte5-best-practices skill to review your Svelte 5 component for correct rune syntax, proper snippet usage, and SvelteKit load function performance optimizations.

Frequently Asked Questions about svelte5-best-practices

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I migrate Svelte 4 reactive statements and stores to Svelte 5 runes?▼

Migrate Svelte 4 reactive statements and stores to Svelte 5 runes by replacing legacy reactive declarations with $state, $derived, and $effect, utilizing step-by-step conversion guidance and automated migration tools for accurate syntax updates.

How do I replace Svelte 4 slots with type-safe snippets in Svelte 5?▼

Replace Svelte 4 slots with type-safe snippets in Svelte 5 by using the new snippet composition syntax, enabling flexible and reusable component design while eliminating legacy slot implementation errors.

How do I fix SSR state isolation and prevent cross-user data exposure in SvelteKit?▼

Fix SSR state isolation and prevent cross-user data exposure in SvelteKit by implementing secure load functions and form actions, ensuring proper server-side state separation to eliminate security vulnerabilities.

What is the correct syntax for Svelte 5 $state, $derived, and $effect runes?▼

Correct syntax for Svelte 5 $state, $derived, and $effect runes involves using these reactive primitives to manage component logic, replacing legacy Svelte 4 patterns to prevent runtime bugs and performance degradation.

How do I optimize SvelteKit load functions for parallel data loading and streaming?▼

Optimize SvelteKit load functions for parallel data loading and streaming by applying performance best practices, ensuring efficient data fetching patterns that resolve suboptimal SvelteKit performance bottlenecks.