clean up event handlers on re-mount (#4493)

CHANGELOG.md

@@ -9,6 +9,7 @@
 * Allow transitions and animations to work within iframes ([#3624](https://github.com/sveltejs/svelte/issues/3624))
 * Fix initialising slot fallbacks when unnecessary ([#3763](https://github.com/sveltejs/svelte/issues/3763))
 * Disallow binding directly to `const` variables ([#4479](https://github.com/sveltejs/svelte/issues/4479))
+* Fix re-attaching event handlers on keyed `{#each}` blocks ([#4491](https://github.com/sveltejs/svelte/issues/4491))
 * Fix updating keyed `{#each}` blocks with `{:else}` ([#4536](https://github.com/sveltejs/svelte/issues/4536), [#4549](https://github.com/sveltejs/svelte/issues/4549))
 * Fix hydration of top-level content ([#4542](https://github.com/sveltejs/svelte/issues/4542))
 

src/compiler/compile/render_dom/Block.ts

@@ -294,10 +294,14 @@ export default class Block {
 
 		if (this.chunks.mount.length === 0) {
 			properties.mount = noop;
-		} else {
+		} else if (this.event_listeners.length === 0) {
 			properties.mount = x`function #mount(#target, anchor) {
 				${this.chunks.mount}
 			}`;
+		} else {
+			properties.mount = x`function #mount(#target, anchor, #remount) {
+				${this.chunks.mount}
+			}`;
 		}
 
 		if (this.has_update_method || this.maintain_context) {
@@ -457,7 +461,10 @@ export default class Block {
 
 			if (this.event_listeners.length === 1) {
 				this.chunks.mount.push(
-					b`${dispose} = ${this.event_listeners[0]};`
+					b`
+						if (#remount) ${dispose}();
+						${dispose} = ${this.event_listeners[0]};
+					`
 				);
 
 				this.chunks.destroy.push(
@@ -465,6 +472,7 @@ export default class Block {
 				);
 			} else {
 				this.chunks.mount.push(b`
+					if (#remount) @run_all(${dispose});
 					${dispose} = [
 						${this.event_listeners}
 					];

src/runtime/internal/keyed_each.ts

@@ -56,7 +56,7 @@ export function update_keyed_each(old_blocks, dirty, get_key, dynamic, ctx, list
 
 	function insert(block) {
 		transition_in(block, 1);
-		block.m(node, next);
+		block.m(node, next, lookup.has(block.key));
 		lookup.set(block.key, block);
 		next = block.first;
 		n--;

test/js/samples/action-custom-event-handler/expected.js

@@ -21,8 +21,9 @@ function create_fragment(ctx) {
 			button = element("button");
 			button.textContent = "foo";
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, button, anchor);
+			if (remount) dispose();
 			dispose = action_destroyer(foo_action = foo.call(null, button, /*foo_function*/ ctx[1]));
 		},
 		p(ctx, [dirty]) {

test/js/samples/action/expected.js

@@ -22,8 +22,9 @@ function create_fragment(ctx) {
 			a.textContent = "Test";
 			attr(a, "href", "#");
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, a, anchor);
+			if (remount) dispose();
 			dispose = action_destroyer(link_action = link.call(null, a));
 		},
 		p: noop,

test/js/samples/bind-online/expected.js

@@ -15,7 +15,9 @@ function create_fragment(ctx) {
 
 	return {
 		c: noop,
-		m(target, anchor) {
+		m(target, anchor, remount) {
+			if (remount) run_all(dispose);
+
 			dispose = [
 				listen(window, "online", /*onlinestatuschanged*/ ctx[1]),
 				listen(window, "offline", /*onlinestatuschanged*/ ctx[1])

test/js/samples/bind-open/expected.js

@@ -21,9 +21,10 @@ function create_fragment(ctx) {
 			details.innerHTML = `<summary>summary</summary>content
 `;
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, details, anchor);
 			details.open = /*open*/ ctx[0];
+			if (remount) dispose();
 			dispose = listen(details, "toggle", /*details_toggle_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/bindings-readonly-order/expected.js

@@ -27,10 +27,11 @@ function create_fragment(ctx) {
 			attr(input0, "type", "file");
 			attr(input1, "type", "file");
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, input0, anchor);
 			insert(target, t, anchor);
 			insert(target, input1, anchor);
+			if (remount) run_all(dispose);
 
 			dispose = [
 				listen(input0, "change", /*input0_change_handler*/ ctx[1]),

test/js/samples/capture-inject-dev-only/expected.js

@@ -29,12 +29,13 @@ function create_fragment(ctx) {
 			t1 = space();
 			input = element("input");
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, p, anchor);
 			append(p, t0);
 			insert(target, t1, anchor);
 			insert(target, input, anchor);
 			set_input_value(input, /*foo*/ ctx[0]);
+			if (remount) dispose();
 			dispose = listen(input, "input", /*input_input_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/component-static-var/expected.js

@@ -36,7 +36,7 @@ function create_fragment(ctx) {
 			t1 = space();
 			input = element("input");
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			mount_component(foo, target, anchor);
 			insert(target, t0, anchor);
 			mount_component(bar, target, anchor);
@@ -44,6 +44,7 @@ function create_fragment(ctx) {
 			insert(target, input, anchor);
 			set_input_value(input, /*z*/ ctx[0]);
 			current = true;
+			if (remount) dispose();
 			dispose = listen(input, "input", /*input_input_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/component-store-reassign-invalidate/expected.js

@@ -32,11 +32,12 @@ function create_fragment(ctx) {
 			button = element("button");
 			button.textContent = "reset";
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, h1, anchor);
 			append(h1, t0);
 			insert(target, t1, anchor);
 			insert(target, button, anchor);
+			if (remount) dispose();
 			dispose = listen(button, "click", /*click_handler*/ ctx[2]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/dont-invalidate-this/expected.js

@@ -18,8 +18,9 @@ function create_fragment(ctx) {
 		c() {
 			input = element("input");
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, input, anchor);
+			if (remount) dispose();
 			dispose = listen(input, "input", make_uppercase);
 		},
 		p: noop,

test/js/samples/event-handler-dynamic/expected.js

@@ -43,7 +43,7 @@ function create_fragment(ctx) {
 			button2 = element("button");
 			button2.textContent = "click";
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, p0, anchor);
 			append(p0, button0);
 			append(p0, t1);
@@ -53,6 +53,7 @@ function create_fragment(ctx) {
 			append(p1, t4);
 			insert(target, t5, anchor);
 			insert(target, button2, anchor);
+			if (remount) run_all(dispose);
 
 			dispose = [
 				listen(button0, "click", /*updateHandler1*/ ctx[2]),

test/js/samples/event-handler-no-passive/expected.js

@@ -21,8 +21,9 @@ function create_fragment(ctx) {
 			a.textContent = "this should not navigate to example.com";
 			attr(a, "href", "https://example.com");
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, a, anchor);
+			if (remount) dispose();
 			dispose = listen(a, "touchstart", touchstart_handler);
 		},
 		p: noop,

test/js/samples/event-modifiers/expected.js

@@ -36,13 +36,14 @@ function create_fragment(ctx) {
 			button2 = element("button");
 			button2.textContent = "or me!";
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, div, anchor);
 			append(div, button0);
 			append(div, t1);
 			append(div, button1);
 			append(div, t3);
 			append(div, button2);
+			if (remount) run_all(dispose);
 
 			dispose = [
 				listen(button0, "click", stop_propagation(prevent_default(handleClick))),

test/js/samples/input-files/expected.js

@@ -21,8 +21,9 @@ function create_fragment(ctx) {
 			attr(input, "type", "file");
 			input.multiple = true;
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, input, anchor);
+			if (remount) dispose();
 			dispose = listen(input, "change", /*input_change_handler*/ ctx[1]);
 		},
 		p: noop,

test/js/samples/input-no-initial-value/expected.js

@@ -32,12 +32,13 @@ function create_fragment(ctx) {
 			attr(input, "type", "text");
 			input.required = true;
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, form, anchor);
 			append(form, input);
 			set_input_value(input, /*test*/ ctx[0]);
 			append(form, t0);
 			append(form, button);
+			if (remount) run_all(dispose);
 
 			dispose = [
 				listen(input, "input", /*input_input_handler*/ ctx[2]),

test/js/samples/input-range/expected.js

@@ -23,9 +23,10 @@ function create_fragment(ctx) {
 			input = element("input");
 			attr(input, "type", "range");
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, input, anchor);
 			set_input_value(input, /*value*/ ctx[0]);
+			if (remount) run_all(dispose);
 
 			dispose = [
 				listen(input, "change", /*input_change_input_handler*/ ctx[1]),

test/js/samples/input-value/expected.js

@@ -31,12 +31,13 @@ function create_fragment(ctx) {
 			t2 = text("!");
 			input.value = /*name*/ ctx[0];
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, input, anchor);
 			insert(target, t0, anchor);
 			insert(target, h1, anchor);
 			append(h1, t1);
 			append(h1, t2);
+			if (remount) dispose();
 			dispose = listen(input, "input", /*onInput*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/input-without-blowback-guard/expected.js

@@ -20,9 +20,10 @@ function create_fragment(ctx) {
 			input = element("input");
 			attr(input, "type", "checkbox");
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, input, anchor);
 			input.checked = /*foo*/ ctx[0];
+			if (remount) dispose();
 			dispose = listen(input, "change", /*input_change_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/instrumentation-script-if-no-block/expected.js

@@ -31,12 +31,13 @@ function create_fragment(ctx) {
 			t2 = text("x: ");
 			t3 = text(/*x*/ ctx[0]);
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, button, anchor);
 			insert(target, t1, anchor);
 			insert(target, p, anchor);
 			append(p, t2);
 			append(p, t3);
+			if (remount) dispose();
 			dispose = listen(button, "click", /*foo*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/instrumentation-script-x-equals-x/expected.js

@@ -32,12 +32,13 @@ function create_fragment(ctx) {
 			t2 = text("number of things: ");
 			t3 = text(t3_value);
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, button, anchor);
 			insert(target, t1, anchor);
 			insert(target, p, anchor);
 			append(p, t2);
 			append(p, t3);
+			if (remount) dispose();
 			dispose = listen(button, "click", /*foo*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/instrumentation-template-if-no-block/expected.js

@@ -31,12 +31,13 @@ function create_fragment(ctx) {
 			t2 = text("x: ");
 			t3 = text(/*x*/ ctx[0]);
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, button, anchor);
 			insert(target, t1, anchor);
 			insert(target, p, anchor);
 			append(p, t2);
 			append(p, t3);
+			if (remount) dispose();
 			dispose = listen(button, "click", /*click_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/instrumentation-template-x-equals-x/expected.js

@@ -32,12 +32,13 @@ function create_fragment(ctx) {
 			t2 = text("number of things: ");
 			t3 = text(t3_value);
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, button, anchor);
 			insert(target, t1, anchor);
 			insert(target, p, anchor);
 			append(p, t2);
 			append(p, t3);
+			if (remount) dispose();
 			dispose = listen(button, "click", /*click_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {

test/js/samples/media-bindings/expected.js

@@ -42,7 +42,7 @@ function create_fragment(ctx) {
 			if (/*seeking*/ ctx[8] === void 0) add_render_callback(() => /*audio_seeking_seeked_handler*/ ctx[17].call(audio));
 			if (/*ended*/ ctx[9] === void 0) add_render_callback(() => /*audio_ended_handler*/ ctx[18].call(audio));
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, audio, anchor);
 
 			if (!isNaN(/*volume*/ ctx[6])) {
@@ -53,6 +53,8 @@ function create_fragment(ctx) {
 				audio.playbackRate = /*playbackRate*/ ctx[7];
 			}
 
+			if (remount) run_all(dispose);
+
 			dispose = [
 				listen(audio, "progress", /*audio_progress_handler*/ ctx[10]),
 				listen(audio, "loadedmetadata", /*audio_loadedmetadata_handler*/ ctx[11]),

test/js/samples/video-bindings/expected.js

@@ -38,9 +38,10 @@ function create_fragment(ctx) {
 			if (/*videoHeight*/ ctx[1] === void 0 || /*videoWidth*/ ctx[2] === void 0) add_render_callback(() => /*video_resize_handler*/ ctx[5].call(video));
 			add_render_callback(() => /*video_elementresize_handler*/ ctx[6].call(video));
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, video, anchor);
 			video_resize_listener = add_resize_listener(video, /*video_elementresize_handler*/ ctx[6].bind(video));
+			if (remount) run_all(dispose);
 
 			dispose = [
 				listen(video, "timeupdate", video_timeupdate_handler),

test/js/samples/window-binding-online/expected.js

@@ -15,7 +15,9 @@ function create_fragment(ctx) {
 
 	return {
 		c: noop,
-		m(target, anchor) {
+		m(target, anchor, remount) {
+			if (remount) run_all(dispose);
+
 			dispose = [
 				listen(window, "online", /*onlinestatuschanged*/ ctx[1]),
 				listen(window, "offline", /*onlinestatuschanged*/ ctx[1])

test/js/samples/window-binding-scroll/expected.js

@@ -34,10 +34,11 @@ function create_fragment(ctx) {
 			t0 = text("scrolled to ");
 			t1 = text(/*y*/ ctx[0]);
 		},
-		m(target, anchor) {
+		m(target, anchor, remount) {
 			insert(target, p, anchor);
 			append(p, t0);
 			append(p, t1);
+			if (remount) dispose();
 
 			dispose = listen(window, "scroll", () => {
 				scrolling = true;

test/runtime/samples/event-handler-each-modifier/_config.js

@@ -0,0 +1,42 @@
+export default {
+	async test({ assert, component, target, window }) {
+		// set first
+		await component.lists.update(() => [
+			{ text: "item1" },
+			{ text: "item2" },
+			{ text: "item3" }
+		]);
+
+		await component.lists.update(() => [
+			{ text: "item3" },
+			{ text: "item2" },
+			{ text: "item1" }
+		]);
+
+		await component.lists.update(() => [
+			{ text: "item1" },
+			{ text: "item2" },
+			{ text: "item3" }
+		]);
+
+		assert.equal(component.updated, 4);
+
+		const [item1, item2] = target.childNodes;
+		const [item1Btn1, item1Btn2] = item1.querySelectorAll('button');
+		const [item2Btn1, item2Btn2] = item2.querySelectorAll('button');
+
+		const clickEvent = new window.MouseEvent('click');
+		
+		await item1Btn1.dispatchEvent(clickEvent);
+		assert.equal(component.getNormalCount(), 1);
+		
+		await item1Btn2.dispatchEvent(clickEvent);
+		assert.equal(component.getModifierCount(), 1);
+
+		await item2Btn1.dispatchEvent(clickEvent);
+		assert.equal(component.getNormalCount(), 2);
+		
+		await item2Btn2.dispatchEvent(clickEvent);
+		assert.equal(component.getModifierCount(), 2);
+	}
+};

test/runtime/samples/event-handler-each-modifier/main.svelte

@@ -0,0 +1,37 @@
+<script>
+	import {afterUpdate} from 'svelte'
+	import {writable} from 'svelte/store'
+	
+	const normal = writable(0);
+	const modifier = writable(0);
+	export let updated = 0;
+	export const lists = writable([]);
+	
+	const click = (e, type) => {
+		if(type === 'normal'){
+			$normal ++;
+		}else{
+			$modifier ++;
+		}
+	}
+	afterUpdate(() => updated++);
+
+	export function getNormalCount() {
+		return $normal;
+	}
+	export function getModifierCount() {
+		return $modifier;
+	}
+</script>
+
+{#each $lists as item (item.text)}
+	<div>
+		{item.text}
+		<button on:click={(e)=>click(e,'normal')}>
+			Normal
+		</button>
+		<button on:click|preventDefault={(e)=> click(e,'modifier')}>
+			Modifier
+		</button>
+	</div>
+{/each}