Melt UI Runes Experiment

Introduction

This is an experiment that aims to migrate existing Melt UI builders to runes.

EDIT: After experimenting with Runes, we're fairly confident in a API to move forward. See the Migration plan for more details.

Credits

Most of the work has been done by Abdelrahman!

New API

The new API relies on classes instead of stores for creating builders.

<!-- previously -->
<script>
	export let open;

	const {
		elements: { trigger, content, arrow },
		states,
	} = createTooltip({
		defaultOpen: open,
		onOpenChange: ({ curr, next }) => {
			open = next;
			return next;
		},
	});

	$: states.open.set(open);
</script>

<button use:melt={$trigger}>Trigger</button>

{#if open}
	<div use:melt={$content}>
		<div use:melt={$arrow} />
		<p>Hello world!</p>
	</div>
{/if}

<!-- now -->
<script>
	let { open } = $props();

	const tooltip = new Tooltip({
		open: {
			get: () => open,
			set: (v) => (open = v),
		},
	});
</script>

<button {...tooltip.trigger()}>Trigger</button>

{#if open}
	<div {...tooltip.content()}>
		<div {...tooltip.arrow()} />
		<p>Hello world!</p>
	</div>
{/if}

I hear you saying "Ugh, classes". Let me explain the reasoning behind this choice:

1. They are more performant, especially with runes. No need for getters and setters for every state.
2. Destructuring makes it hard to use multiple builders in the same page because you need to rename multiple variables. This is no longer the case with the new API.

Usage

Try out the new API yourself by cloning this repo.

git clone https://github.com/melt-ui/runes-experiment.git

You'll find three builders have been migrated to runes.

1. Label
2. Toggle
3. Tooltip

import { Label, Toggle, Tooltip } from "$lib/index.js";

You'll also find an example for each builder under the src/routes/playground directory.