fix

packages/svelte/src/internal/client/dom/elements/transitions.js

@@ -163,22 +163,12 @@ export function bind_transition(element, get_fn, get_params, direction, global)
 	let callbacks = [];
 
 	/** @param {number} target */
-	function go(target) {
+	function start(target) {
 		// TODO if this is an `in:` transition and we just called `out()`, do nothing (let it play until the block is destroyed, probably immediately)
 		// TODO if this is an `out:` transition and we just called `in()`, abort everything and reset to 1 immediately
 		// TODO add a `transition.abort()` method to cancel an outro transition immediately when an effect is destroyed before the transition finishes running — don't want tickers etc to continue
 
-		if (current_task) {
-			current_task.abort();
-			current_task = null;
-		}
-
-		if (current_animation && current_options) {
-			const time = /** @type {number} */ (current_animation.currentTime);
-			const duration = /** @type {number} */ (current_options.duration);
-			p = (Math.abs(current_delta) * time) / duration;
-			current_animation.cancel();
-		}
+		stop();
 
 		current_options ??= get_fn()(element, get_params?.(), { direction });
 
@@ -251,6 +241,21 @@ export function bind_transition(element, get_fn, get_params, direction, global)
 		}
 	}
 
+	function stop() {
+		if (current_task) {
+			current_task.abort();
+			current_task = null;
+		}
+
+		if (current_animation && current_options) {
+			const time = /** @type {number} */ (current_animation.currentTime);
+			const duration = /** @type {number} */ (current_options.duration);
+			p = (Math.abs(current_delta) * time) / duration;
+			current_animation.cancel();
+			current_animation = null;
+		}
+	}
+
 	/** @type {import('#client').Transition2} */
 	// TODO this needs to be `in()` and `out()` rather than `to()`, and both
 	// need to be idempotent (because of `{#if ...}{#if ...}`). `out()` should
@@ -259,19 +264,35 @@ export function bind_transition(element, get_fn, get_params, direction, global)
 	const transition = {
 		global,
 		in() {
-			if (current_direction === TRANSITION_IN) return;
-
-			current_direction = TRANSITION_IN;
 			callbacks = [];
-			go(1);
+
+			if (direction === 'in' || direction === 'both') {
+				if (current_direction !== TRANSITION_IN) {
+					current_direction = TRANSITION_IN;
+					start(1);
+				}
+			} else {
+				current_direction = 0;
+				stop();
+			}
 		},
 		out(callback) {
-			if (callback) callbacks.push(callback);
-			if (current_direction === TRANSITION_OUT) return;
+			if (direction === 'out' || direction === 'both') {
+				if (callback) {
+					callbacks.push(callback);
+				}
 
-			current_direction = TRANSITION_OUT;
-			go(0);
-		}
+				if (current_direction !== TRANSITION_OUT) {
+					current_direction = TRANSITION_OUT;
+					start(0);
+				}
+			} else {
+				if (callback) {
+					callback();
+				}
+			}
+		},
+		stop
 	};
 
 	(effect.transitions ??= []).push(transition);

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

@@ -232,23 +232,30 @@ export function render_effect(fn, block = current_block, managed = false, sync =
 }
 
 /**
- * @param {import('#client').Effect} signal
+ * @param {import('#client').Effect} effect
  * @returns {void}
  */
-export function destroy_effect(signal) {
-	destroy_children(signal);
-	remove_reactions(signal, 0);
-	set_signal_status(signal, DESTROYED);
-
-	signal.teardown?.();
-	signal.ondestroy?.();
-	signal.fn =
-		signal.effects =
-		signal.teardown =
-		signal.ondestroy =
-		signal.ctx =
-		signal.block =
-		signal.deps =
+export function destroy_effect(effect) {
+	destroy_children(effect);
+	remove_reactions(effect, 0);
+	set_signal_status(effect, DESTROYED);
+
+	if (effect.transitions) {
+		for (const transition of effect.transitions) {
+			transition.stop();
+		}
+	}
+
+	effect.teardown?.();
+	effect.ondestroy?.();
+
+	effect.fn =
+		effect.effects =
+		effect.teardown =
+		effect.ondestroy =
+		effect.ctx =
+		effect.block =
+		effect.deps =
 			null;
 }
 

packages/svelte/src/internal/client/types.d.ts

@@ -331,6 +331,7 @@ export interface Transition2 {
 	global: boolean;
 	in: () => void;
 	out: (callback?: () => void) => void;
+	stop: () => void;
 }
 
 export * from './reactivity/types';