A simple Svelte todo app, copy paste this in the src/App.svelte file in the svelte boilerplate.

App.svelte

<script>
	let task = "";
	let todos = ["eat", "sleep", "code"]

	function addTask() {
		if(task!=""){
			todos.push(task)
			todos = todos;
			task = ""
		}
	}

	function addNew(event) {
		if (event.which === 13) {
			addTask()
		}
	}

	function removeTask(index) {
		todos = todos.slice(0, index).concat(todos.slice(index + 1));
		console.log(index);
	}
</script>

<style>
	ul {
		list-style: none;
	}
</style>

<input bind:value={task} on:keydown={addNew}>
<button on:click={addTask}>Add Task</button>

<ul>
	{#each todos as todo, index (todo)}
		<li>
			<input type=checkbox on:click={() => removeTask(index)}>
			{todo}
		</li>
	{/each}
</ul>