<p>{{x}}</p>

<script>
	let _x;

	function getX () {
		return _x;
	}

	export default {
		data () {
			return {
				y: 1
			};
		},

		computed: {
			xGetter ( y ) {
				_x = y * 2;
				return getX;
			},

			x ( xGetter ) {
				return xGetter();
			}
		}
	};
</script>