guarantee fork

Author: Rich-Harris

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

@@ -1,5 +1,5 @@
 /** @import { Effect, TemplateNode, Value } from '#client' */
-
+/** @import { Fork } from '../../reactivity/forks.js' */
 import { async_derived } from '../../reactivity/deriveds.js';
 import { active_fork } from '../../reactivity/forks.js';
 import { active_effect, schedule_effect } from '../../runtime.js';
@@ -13,15 +13,16 @@ import { capture } from './boundary.js';
 export function async(node, expressions, fn) {
 	// TODO handle hydration
 
-	var fork = active_fork;
+	var fork = /** @type {Fork} */ (active_fork);
 	var effect = /** @type {Effect} */ (active_effect);
+
 	var restore = capture();
 
 	Promise.all(expressions.map((fn) => async_derived(fn))).then((result) => {
 		restore();
 		fn(node, ...result);
 
-		fork?.run(() => {
+		fork.run(() => {
 			schedule_effect(effect);
 		});
 	});

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

@@ -24,7 +24,7 @@ import { queue_boundary_micro_task } from '../task.js';
 import * as e from '../../../shared/errors.js';
 import { DEV } from 'esm-env';
 import { from_async_derived, set_from_async_derived } from '../../reactivity/deriveds.js';
-import { active_fork, Fork } from '../../reactivity/forks.js';
+import { Fork } from '../../reactivity/forks.js';
 
 /**
  * @typedef {{

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

@@ -1,4 +1,5 @@
 /** @import { EachItem, EachState, Effect, MaybeSource, Source, TemplateNode, TransitionManager, Value } from '#client' */
+/** @import { Fork } from '../../reactivity/forks.js'; */
 import {
 	EACH_INDEX_REACTIVE,
 	EACH_IS_ANIMATED,
@@ -266,8 +267,9 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 				fallback = branch(() => fallback_fn(anchor));
 			}
 		} else {
-			if (active_fork !== null && should_defer_append()) {
+			if (should_defer_append()) {
 				var keys = new Set();
+				var fork = /** @type {Fork} */ (active_fork);
 
 				for (i = 0; i < length; i += 1) {
 					value = array[i];
@@ -303,11 +305,11 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 
 				for (const [key, item] of state.items) {
 					if (!keys.has(key)) {
-						active_fork.skipped_effects.add(item.e);
+						fork.skipped_effects.add(item.e);
 					}
 				}
 
-				active_fork?.add_callback(commit);
+				fork.add_callback(commit);
 			} else {
 				commit();
 			}

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

@@ -1,4 +1,5 @@
 /** @import { Effect, TemplateNode } from '#client' */
+/** @import { Fork } from '../../reactivity/forks.js'; */
 import { EFFECT_TRANSPARENT } from '#client/constants';
 import {
 	hydrate_next,
@@ -112,7 +113,7 @@ export function if_block(node, fn, elseif = false) {
 			}
 		}
 
-		var defer = active_fork !== null && should_defer_append();
+		var defer = should_defer_append();
 		var target = anchor;
 
 		if (defer) {
@@ -125,13 +126,15 @@ export function if_block(node, fn, elseif = false) {
 		}
 
 		if (defer) {
+			var fork = /** @type {Fork} */ (active_fork);
+
 			const skipped = condition ? alternate_effect : consequent_effect;
 			if (skipped !== null) {
 				// TODO need to do this for other kinds of blocks
-				active_fork?.skipped_effects.add(skipped);
+				fork.skipped_effects.add(skipped);
 			}
 
-			active_fork?.add_callback(commit);
+			fork.add_callback(commit);
 		} else {
 			commit();
 		}

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

@@ -1,4 +1,5 @@
 /** @import { Effect, TemplateNode } from '#client' */
+/** @import { Fork } from '../../reactivity/forks.js'; */
 import { UNINITIALIZED } from '../../../../constants.js';
 import { block, branch, pause_effect } from '../../reactivity/effects.js';
 import { not_equal, safe_not_equal } from '../../reactivity/equality.js';
@@ -55,7 +56,7 @@ export function key_block(node, get_key, render_fn) {
 		if (changed(key, (key = get_key()))) {
 			var target = anchor;
 
-			var defer = active_fork !== null && should_defer_append();
+			var defer = should_defer_append();
 
 			if (defer) {
 				offscreen_fragment = document.createDocumentFragment();
@@ -65,7 +66,7 @@ export function key_block(node, get_key, render_fn) {
 			pending_effect = branch(() => render_fn(target));
 
 			if (defer) {
-				active_fork?.add_callback(commit);
+				/** @type {Fork} */ (active_fork).add_callback(commit);
 			} else {
 				commit();
 			}

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

@@ -1,4 +1,5 @@
 /** @import { TemplateNode, Dom, Effect } from '#client' */
+/** @import { Fork } from '../../reactivity/forks.js'; */
 import { EFFECT_TRANSPARENT } from '#client/constants';
 import { block, branch, pause_effect } from '../../reactivity/effects.js';
 import { active_fork } from '../../reactivity/forks.js';
@@ -53,7 +54,7 @@ export function component(node, get_component, render_fn) {
 	block(() => {
 		if (component === (component = get_component())) return;
 
-		var defer = active_fork !== null && should_defer_append();
+		var defer = should_defer_append();
 
 		if (component) {
 			var target = anchor;
@@ -67,7 +68,7 @@ export function component(node, get_component, render_fn) {
 		}
 
 		if (defer) {
-			active_fork?.add_callback(commit);
+			/** @type {Fork} */ (active_fork).add_callback(commit);
 		} else {
 			commit();
 		}

packages/svelte/src/internal/client/reactivity/effects.js

@@ -343,7 +343,7 @@ export function template_effect(fn, sync = [], async = [], d = derived) {
 	var parent = /** @type {Effect} */ (active_effect);
 
 	if (async.length > 0) {
-		var fork = active_fork;
+		var fork = /** @type {Fork} */ (active_fork);
 		var restore = capture();
 
 		Promise.all(async.map((expression) => async_derived(expression))).then((result) => {
@@ -355,11 +355,9 @@ export function template_effect(fn, sync = [], async = [], d = derived) {
 
 			var effect = create_template_effect(fn, [...sync.map(d), ...result]);
 
-			if (fork !== null) {
-				fork.run(() => {
-					schedule_effect(effect);
-				});
-			}
+			fork.run(() => {
+				schedule_effect(effect);
+			});
 		});
 	} else {
 		create_template_effect(fn, sync.map(d));