chore: simplify effect.dom stuff (#11752)

Author: Rich-Harris

packages/svelte/src/internal/client/dom/blocks/html.js

@@ -4,7 +4,6 @@ import { current_effect, get } from '../../runtime.js';
 import { is_array } from '../../utils.js';
 import { hydrate_nodes, hydrating } from '../hydration.js';
 import { create_fragment_from_html, remove } from '../reconciler.js';
-import { push_template_node } from '../template.js';
 
 /**
  * @param {import('#client').Effect} effect
@@ -38,7 +37,7 @@ export function html(anchor, get_value, svg, mathml) {
 	let value = derived(get_value);
 
 	render_effect(() => {
-		var dom = html_to_dom(anchor, parent_effect, get(value), svg, mathml);
+		var dom = html_to_dom(anchor, get(value), svg, mathml);
 
 		if (dom) {
 			return () => {
@@ -56,13 +55,12 @@ export function html(anchor, get_value, svg, mathml) {
  * inserts it before the target anchor and returns the new nodes.
  * @template V
  * @param {Element | Text | Comment} target
- * @param {import('#client').Effect | null} effect
  * @param {V} value
  * @param {boolean} svg
  * @param {boolean} mathml
  * @returns {Element | Comment | (Element | Comment | Text)[]}
  */
-function html_to_dom(target, effect, value, svg, mathml) {
+function html_to_dom(target, value, svg, mathml) {
 	if (hydrating) return hydrate_nodes;
 
 	var html = value + '';
@@ -81,9 +79,6 @@ function html_to_dom(target, effect, value, svg, mathml) {
 	if (node.childNodes.length === 1) {
 		var child = /** @type {Text | Element | Comment} */ (node.firstChild);
 		target.before(child);
-		if (effect !== null) {
-			push_template_node(child, effect);
-		}
 		return child;
 	}
 
@@ -97,9 +92,5 @@ function html_to_dom(target, effect, value, svg, mathml) {
 		target.before(node);
 	}
 
-	if (effect !== null) {
-		push_template_node(nodes, effect);
-	}
-
 	return nodes;
 }

packages/svelte/src/internal/client/dom/blocks/svelte-element.js

@@ -6,37 +6,13 @@ import {
 	branch,
 	destroy_effect,
 	pause_effect,
-	render_effect,
 	resume_effect
 } from '../../reactivity/effects.js';
-import { is_array } from '../../utils.js';
 import { set_should_intro } from '../../render.js';
 import { current_each_item, set_current_each_item } from './each.js';
-import { current_component_context, current_effect } from '../../runtime.js';
-import { push_template_node } from '../template.js';
+import { current_component_context } from '../../runtime.js';
 import { DEV } from 'esm-env';
 
-/**
- * @param {import('#client').Effect} effect
- * @param {Element} from
- * @param {Element} to
- * @returns {void}
- */
-function swap_block_dom(effect, from, to) {
-	const dom = effect.dom;
-
-	if (is_array(dom)) {
-		for (let i = 0; i < dom.length; i++) {
-			if (dom[i] === from) {
-				dom[i] = to;
-				break;
-			}
-		}
-	} else if (dom === from) {
-		effect.dom = to;
-	}
-}
-
 /**
  * @param {Comment} anchor
  * @param {() => string} get_tag
@@ -47,8 +23,6 @@ function swap_block_dom(effect, from, to) {
  * @returns {void}
  */
 export function element(anchor, get_tag, is_svg, render_fn, get_namespace, location) {
-	const parent_effect = /** @type {import('#client').Effect} */ (current_effect);
-
 	const filename = DEV && location && current_component_context?.function.filename;
 
 	/** @type {string | null} */
@@ -104,7 +78,6 @@ export function element(anchor, get_tag, is_svg, render_fn, get_namespace, locat
 
 		if (next_tag && next_tag !== current_tag) {
 			effect = branch(() => {
-				const prev_element = element;
 				element = hydrating
 					? /** @type {Element} */ (hydrate_nodes[0])
 					: ns
@@ -144,12 +117,9 @@ export function element(anchor, get_tag, is_svg, render_fn, get_namespace, locat
 
 				anchor.before(element);
 
-				if (prev_element) {
-					swap_block_dom(parent_effect, prev_element, element);
-					prev_element.remove();
-				} else if (!hydrating) {
-					push_template_node(element, parent_effect);
-				}
+				return () => {
+					element?.remove();
+				};
 			});
 		}
 

packages/svelte/src/internal/client/dom/template.js

@@ -9,27 +9,15 @@ import { is_array } from '../utils.js';
 /**
  * @template {import("#client").TemplateNode | import("#client").TemplateNode[]} T
  * @param {T} dom
- * @param {import("#client").Effect} effect
  * @returns {T}
  */
-export function push_template_node(
-	dom,
-	effect = /** @type {import('#client').Effect} */ (current_effect)
-) {
-	var current_dom = effect.dom;
-	if (current_dom === null) {
-		effect.dom = dom;
-	} else {
-		if (!is_array(current_dom)) {
-			current_dom = effect.dom = [current_dom];
-		}
+function push_template_node(dom) {
+	var effect = /** @type {import('#client').Effect} */ (current_effect);
 
-		if (is_array(dom)) {
-			current_dom.push(...dom);
-		} else {
-			current_dom.push(dom);
-		}
+	if (effect.dom === null) {
+		effect.dom = dom;
 	}
+
 	return dom;
 }
 
@@ -55,15 +43,8 @@ export function template(content, flags) {
 			node = create_fragment_from_html(content);
 			if (!is_fragment) node = /** @type {Node} */ (node.firstChild);
 		}
-		var clone = use_import_node ? document.importNode(node, true) : node.cloneNode(true);
 
-		push_template_node(
-			is_fragment
-				? /** @type {import('#client').TemplateNode[]} */ ([...clone.childNodes])
-				: /** @type {import('#client').TemplateNode} */ (clone)
-		);
-
-		return clone;
+		return use_import_node ? document.importNode(node, true) : node.cloneNode(true);
 	};
 }
 
@@ -123,15 +104,7 @@ export function ns_template(content, flags, ns = 'svg') {
 			}
 		}
 
-		var clone = node.cloneNode(true);
-
-		push_template_node(
-			is_fragment
-				? /** @type {import('#client').TemplateNode[]} */ ([...clone.childNodes])
-				: /** @type {import('#client').TemplateNode} */ (clone)
-		);
-
-		return clone;
+		return node.cloneNode(true);
 	};
 }
 
@@ -206,7 +179,7 @@ function run_scripts(node) {
  */
 /*#__NO_SIDE_EFFECTS__*/
 export function text(anchor) {
-	if (!hydrating) return push_template_node(empty());
+	if (!hydrating) return empty();
 
 	var node = hydrate_nodes[0];
 
@@ -227,7 +200,6 @@ export function comment() {
 	var frag = document.createDocumentFragment();
 	var anchor = empty();
 	frag.append(anchor);
-	push_template_node([anchor]);
 
 	return frag;
 }
@@ -236,10 +208,18 @@ export function comment() {
  * Assign the created (or in hydration mode, traversed) dom elements to the current block
  * and insert the elements into the dom (in client mode).
  * @param {Text | Comment | Element} anchor
- * @param {import('#client').Dom} dom
+ * @param {DocumentFragment | Element | Comment} node
  */
-export function append(anchor, dom) {
+export function append(anchor, node) {
 	if (!hydrating) {
-		anchor.before(/** @type {Node} */ (dom));
+		/** @type {import('#client').Dom} */
+		const dom =
+			node.nodeType === 11
+				? /** @type {import('#client').TemplateNode[]} */ ([...node.childNodes])
+				: /** @type {Element | Comment} */ (node);
+
+		/** @type {import('#client').Effect} */ (current_effect).dom = dom;
+
+		anchor.before(/** @type {Node} */ (node));
 	}
 }