Function create_item

packages/svelte/src/internal/client/dom/blocks/each.js:668–698

* @template V * @param {Map<any, EachItem>} items * @param {Node} anchor * @param {V} value * @param {unknown} key * @param {number} index * @param {(anchor: Node, item: V | Source<V>, index: number | Value<number>, collection: () => V[]) => void} render_fn * @param {number} flags * @param {

(items, anchor, value, key, index, render_fn, flags, get_collection)

 * @returns {EachItem}
 */
function create_item(items, anchor, value, key, index, render_fn, flags, get_collection) {
	var v =
		(flags & EACH_ITEM_REACTIVE) !== 0
			? (flags & EACH_ITEM_IMMUTABLE) === 0
				? mutable_source(value, false, false)
				: source(value)
			: null;

	var i = (flags & EACH_INDEX_REACTIVE) !== 0 ? source(index) : null;

	if (DEV && v) {
		// For tracing purposes, we need to link the source signal we create with the
		// collection + index so that tracing works as intended
		v.trace = () => {
			// eslint-disable-next-line @typescript-eslint/no-unused-expressions
			get_collection()[i?.v ?? index];
		};
	}

	return {
		v,
		i,
		e: branch(() => {
			render_fn(anchor, v ?? value, i ?? index, get_collection);

			return () => {
				items.delete(key);
			};
		})
	};
}

/**
 * @param {Effect} effect