Svelte Core Bestpractices

Comprehensive reference for writing modern Svelte 5 code using runes instead of legacy patterns. Load this when working on any Svelte component to get guidance on reactivity ($state, $derived), proper use of $effect (sparingly), event handling, snippets over slots, and CSS scoping. The advice is opinionated in the right ways: it'll steer you toward $derived instead of effects for computed values, remind you to key your each blocks, and suggest context over shared modules for state. Especially helpful if you're migrating from Svelte 4 or keep reaching for old patterns like export let and $: statements. The $inspect.trace tip alone is worth having loaded when debugging reactive updates.