Modifying initial prop (or: copy prop to data)

I have a component presenting a list of items which are gradually removed (think of it like visual ‘reduce’ functionality).

So basically, the custom component receives items as a prop array and it is supposed keep removing items from this array, therefore it makes sense to copy over the array into data.

A lot of sites on the internet says this is possible (example), but somehow the code below does not work for me:

    export default Vue.extend({
        data() {
            return {
                itemsModel: [...this.items] as Item[],
            };
        },
        props: {
            items: Array as PropType<Item[]>,
        },
    });

When I inspect the component on the page, items correctly contains the items, but itemsModel is an empty array.

Also, it is not clear to me what happens to itemsModel if the parent decides to change items and finally, I’m wondering if having setters for props might make it more idiomatic and obvious.