AddList.svelte

<script>
    export let component;
    export let config;
    export let items;
    export let component_id;

    let idIncrement = 0;

    $items.forEach((item) => {
        item.__id = idIncrement;
        idIncrement++;
    });

    function addItem() {
        var l = $items.length;
        $items[l] = {
            __id: idIncrement,
        };
        idIncrement++;
    }

    function removeItemFn(i) {
        return () => {
            $items = $items.filter(function (value, index, arr) {
                if (value.__id != i) return value;
            });
        };
    }
</script>

<ul>
    {#each $items as item}
        <li>
            <svelte:component
                this={component}
                objAttributes={item}
                config={config}
                id={component_id}
                removeFn={removeItemFn(item.__id)}
            />
        </li>
    {/each}
</ul>
<button on:click={addItem}>
    <slot />
</button>