Split $.each into $.each_keyed/$.each_indexed

Author: trueadm

.github/PULL_REQUEST_TEMPLATE.md

@@ -4,7 +4,6 @@ Please note that [the Svelte codebase is currently being rewritten for Svelte 5]
 
 If your PR concerns Svelte 4 (including updates to [svelte.dev.docs](https://svelte.dev/docs)), please ensure the base branch is `svelte-4` and not `main`.
 
-
 ### Before submitting the PR, please make sure you do the following
 
 - [ ] It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs

packages/svelte/src/compiler/phases/3-transform/client/visitors/template.js

@@ -2227,19 +2227,34 @@ export const template_visitors = {
 			declarations.push(b.let(node.index, index));
 		}
 
-		context.state.after_update.push(
-			b.stmt(
-				b.call(
-					'$.each',
-					context.state.node,
-					each_node_meta.array_name ? each_node_meta.array_name : b.thunk(collection),
-					b.literal(each_type),
-					key_function,
-					b.arrow([b.id('$$anchor'), item, index], b.block(declarations.concat(children))),
-					else_block
+		if ((each_type & EACH_KEYED) !== 0) {
+			context.state.after_update.push(
+				b.stmt(
+					b.call(
+						'$.each_keyed',
+						context.state.node,
+						each_node_meta.array_name ? each_node_meta.array_name : b.thunk(collection),
+						b.literal(each_type),
+						key_function,
+						b.arrow([b.id('$$anchor'), item, index], b.block(declarations.concat(children))),
+						else_block
+					)
 				)
-			)
-		);
+			);
+		} else {
+			context.state.after_update.push(
+				b.stmt(
+					b.call(
+						'$.each_indexed',
+						context.state.node,
+						each_node_meta.array_name ? each_node_meta.array_name : b.thunk(collection),
+						b.literal(each_type),
+						b.arrow([b.id('$$anchor'), item, index], b.block(declarations.concat(children))),
+						else_block
+					)
+				)
+			);
+		}
 	},
 	IfBlock(node, context) {
 		context.state.template.push('<!>');

packages/svelte/src/internal/client/reconciler.js

@@ -260,9 +260,9 @@ export function reconcile_indexed_array(
  * @param {Element | Comment | Text} dom
  * @param {boolean} is_controlled
  * @param {(anchor: null, item: V, index: number | import('./types.js').Signal<number>) => void} render_fn
- * @param {Array<string> | null} keys
  * @param {number} flags
  * @param {boolean} apply_transitions
+ * @param {Array<string> | null} keys
  * @returns {void}
  */
 export function reconcile_tracked_array(
@@ -271,9 +271,9 @@ export function reconcile_tracked_array(
 	dom,
 	is_controlled,
 	render_fn,
-	keys,
 	flags,
-	apply_transitions
+	apply_transitions,
+	keys
 ) {
 	var a_blocks = each_block.items;
 	const is_computed_key = keys !== null;

packages/svelte/src/internal/client/render.js

@@ -2263,9 +2263,10 @@ export function each_item_block(item, key, index, render_fn, flags) {
  * @param {null | ((item: V) => string)} key_fn
  * @param {(anchor: null, item: V, index: import('./types.js').MaybeSignal<number>) => void} render_fn
  * @param {null | ((anchor: Node) => void)} fallback_fn
+ * @param {typeof reconcile_indexed_array | reconcile_tracked_array} reconcile_fn
  * @returns {void}
  */
-export function each(anchor_node, collection, flags, key_fn, render_fn, fallback_fn) {
+function each(anchor_node, collection, flags, key_fn, render_fn, fallback_fn, reconcile_fn) {
 	const is_controlled = (flags & EACH_IS_CONTROLLED) !== 0;
 	const block = create_each_block(flags, anchor_node);
 
@@ -2385,20 +2386,7 @@ export function each(anchor_node, collection, flags, key_fn, render_fn, fallback
 			const flags = block.flags;
 			const is_controlled = (flags & EACH_IS_CONTROLLED) !== 0;
 			const anchor_node = block.anchor;
-			if ((flags & EACH_KEYED) !== 0) {
-				reconcile_tracked_array(
-					array,
-					block,
-					anchor_node,
-					is_controlled,
-					render_fn,
-					keys,
-					flags,
-					true
-				);
-			} else {
-				reconcile_indexed_array(array, block, anchor_node, is_controlled, render_fn, flags, true);
-			}
+			reconcile_fn(array, block, anchor_node, is_controlled, render_fn, flags, true, keys);
 		},
 		block,
 		true
@@ -2426,6 +2414,33 @@ export function each(anchor_node, collection, flags, key_fn, render_fn, fallback
 	block.effect = each;
 }
 
+/**
+ * @template V
+ * @param {Element | Comment} anchor_node
+ * @param {() => V[]} collection
+ * @param {number} flags
+ * @param {null | ((item: V) => string)} key_fn
+ * @param {(anchor: null, item: V, index: import('./types.js').MaybeSignal<number>) => void} render_fn
+ * @param {null | ((anchor: Node) => void)} fallback_fn
+ * @returns {void}
+ */
+export function each_keyed(anchor_node, collection, flags, key_fn, render_fn, fallback_fn) {
+	each(anchor_node, collection, flags, key_fn, render_fn, fallback_fn, reconcile_tracked_array);
+}
+
+/**
+ * @template V
+ * @param {Element | Comment} anchor_node
+ * @param {() => V[]} collection
+ * @param {number} flags
+ * @param {(anchor: null, item: V, index: import('./types.js').MaybeSignal<number>) => void} render_fn
+ * @param {null | ((anchor: Node) => void)} fallback_fn
+ * @returns {void}
+ */
+export function each_indexed(anchor_node, collection, flags, render_fn, fallback_fn) {
+	each(anchor_node, collection, flags, null, render_fn, fallback_fn, reconcile_indexed_array);
+}
+
 /**
  * @param {Element | Text | Comment} anchor
  * @param {boolean} is_html