SvelteKit Patterns

Quick Start

// Query: Read data
export const get_contacts = query(() =>
	db.prepare('SELECT * FROM contacts').all(),
);

// Form: Validated mutation with redirect
export const create = form(
	v.object({ name: v.string() }),
	async ({ name }) => {
		db.prepare('INSERT INTO contacts ...').run(id, name);
		redirect(303, '/contacts');
	},
);

// Command: Mutation with refresh
export const delete_contact = command(v.string(), async (id) => {
	db.prepare('DELETE FROM contacts WHERE id = ?').run(id);
	await get_contacts().refresh();
	return { success: true };
});

Core Principles

• Types: query (read), form (mutations + redirects), command

(mutations only)

• Validation: Use valibot schemas for all inputs
• Security: Always include user_id in WHERE clauses
• Batching: Use query.batch() for N+1 prevention
• Refresh: Call .refresh() in form/command handlers
• Use .current: Store queries in variables, check

.current === undefined for initial load

• No manual keys: Never use refresh_key++ or {#key} blocks
• Return values: Commands must return { success: true }

Reference Files

• [remote-functions.md](references/remote-functions.md) - Complete

remote functions API

• [routing.md](references/routing.md) - File-based routing patterns
• [database-patterns.md](references/database-patterns.md) - Advanced

database queries