svelte/test/runtime/samples/component-binding-invalid-identifier/Counter.html

<button on:click='set({ "x-count": state["x-count"] + 1 })'>+1</button>

<script>
	export default {
		data: () => ({
			"x-count": 0
		}),
		computed: {
			state(arg)  {
				return arg;
			}
		}
	};
</script>