<script>
let myFavNums = [5, 12, 55, 81];
$: myFavNumsTotal = myFavNums.reduce((a, b) => a + b);
$: {
console.log('Updated: ' + myFavNums);
}
const addFavNum = () => {
myFavNums = [...myFavNums, 65];
}
</script>
<h1>Fav Total: {myFavNumsTotal}</h1>
<button on:click={() => addFavNum()}>Add Item</button>