svelte/site/content/tutorial/09-motion/02-spring/app-a/App.svelte

<script>
	import { writable } from 'svelte/store';

	let coords = writable({ x: 50, y: 50 });
	let size = writable(10);
</script>

<style>
	svg { width: 100%; height: 100%; margin: -8px; }
	circle { fill: #ff3e00 }
</style>

<div style="position: absolute; right: 1em;">
	<label>
		<h3>stiffness ({coords.stiffness})</h3>
		<input bind:value={coords.stiffness} type="range" min="0" max="1" step="0.01">
	</label>

	<label>
		<h3>damping ({coords.damping})</h3>
		<input bind:value={coords.damping} type="range" min="0" max="1" step="0.01">
	</label>
</div>

<svg
	on:mousemove="{e => coords.set({ x: e.clientX, y: e.clientY })}"
	on:mousedown="{() => size.set(30)}"
	on:mouseup="{() => size.set(10)}"
>
	<circle cx={$coords.x} cy={$coords.y} r={$size}/>
</svg>