src/routes/+page.svelte

<script lang="ts">
	import { goto } from "$app/navigation";
	import { base } from "$app/paths";
	import ChatWindow from "$lib/components/chat/ChatWindow.svelte";
	import { pendingMessage } from "$lib/stores/pendingMessage";

	let loading = false;

	async function createConversation(message: string) {
		try {
			loading = true;
			const res = await fetch(`${base}/conversation`, {
				method: "POST",
				headers: {
					"Content-Type": "application/json",
				},
			});

			if (!res.ok) {
				alert("Error while creating conversation: " + (await res.text()));
				return;
			}

			const { conversationId } = await res.json();

			// Ugly hack to use a store as temp storage, feel free to improve ^^
			pendingMessage.set(message);

			// invalidateAll to update list of conversations
			await goto(`${base}/conversation/${conversationId}`, { invalidateAll: true });
		} finally {
			loading = false;
		}
	}
</script>

<ChatWindow on:message={(ev) => createConversation(ev.detail)} {loading} />