<button on:tap='set({ z: z + 1 })'>{{z}}</button> <script> export default { data: () => ({ z: 10 }), events: { tap ( node, callback ) { const clickHandler = event => { callback(event); }; node.addEventListener( 'click', clickHandler, false ); return { teardown () { node.addEventListener( 'click', clickHandler, false ); } }; } } }; </script>