From fb534a3d501be11347d43dbc59e1063be91ec1fb Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Wed, 30 Jan 2019 14:26:55 -0500
Subject: [PATCH 1/5] return promise from nextTick

---
 src/internal/scheduler.js | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/src/internal/scheduler.js b/src/internal/scheduler.js
index 4d9f9ad388..bc4e14b96d 100644
--- a/src/internal/scheduler.js
+++ b/src/internal/scheduler.js
@@ -4,14 +4,13 @@ import { set_current_component } from './lifecycle.js';
 export let dirty_components = [];
 export const intros = { enabled: false };
 
-let update_scheduled = false;
+let update_promise;
 const binding_callbacks = [];
 const render_callbacks = [];
 
 export function schedule_update() {
-	if (!update_scheduled) {
-		update_scheduled = true;
-		queue_microtask(flush);
+	if (!update_promise) {
+		update_promise = Promise.resolve().then(flush);
 	}
 }
 
@@ -22,6 +21,7 @@ export function add_render_callback(fn) {
 export function nextTick(fn) {
 	add_render_callback(fn);
 	schedule_update();
+	return update_promise;
 }
 
 export function add_binding_callback(fn) {
@@ -56,7 +56,7 @@ export function flush() {
 		}
 	} while (dirty_components.length);
 
-	update_scheduled = false;
+	update_promise = null;
 }
 
 function update($$) {
@@ -68,10 +68,4 @@ function update($$) {
 
 		$$.after_render.forEach(add_render_callback);
 	}
-}
-
-function queue_microtask(callback) {
-	Promise.resolve().then(() => {
-		if (update_scheduled) callback();
-	});
 }
\ No newline at end of file

From 3c1734c1fc022133f65685e0ab128f2d4924d7c9 Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Wed, 30 Jan 2019 14:27:39 -0500
Subject: [PATCH 2/5] make callback optional

---
 src/internal/scheduler.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/internal/scheduler.js b/src/internal/scheduler.js
index bc4e14b96d..7292c85f07 100644
--- a/src/internal/scheduler.js
+++ b/src/internal/scheduler.js
@@ -19,7 +19,7 @@ export function add_render_callback(fn) {
 }
 
 export function nextTick(fn) {
-	add_render_callback(fn);
+	if (fn) add_render_callback(fn);
 	schedule_update();
 	return update_promise;
 }

From 3ea5f3b8f0e93180acca730316e3c2b1c9469375 Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Wed, 30 Jan 2019 15:06:06 -0500
Subject: [PATCH 3/5] rename to tick, remove callback interface

---
 index.mjs                                          | 2 +-
 src/internal/scheduler.js                          | 3 +--
 test/runtime/samples/lifecycle-next-tick/main.html | 4 ++--
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/index.mjs b/index.mjs
index 768b53f626..ee5b575171 100644
--- a/index.mjs
+++ b/index.mjs
@@ -5,6 +5,6 @@ export {
 	afterUpdate,
 	setContext,
 	getContext,
-	nextTick,
+	tick,
 	createEventDispatcher
 } from './internal';
diff --git a/src/internal/scheduler.js b/src/internal/scheduler.js
index 7292c85f07..717a5c7ff4 100644
--- a/src/internal/scheduler.js
+++ b/src/internal/scheduler.js
@@ -18,8 +18,7 @@ export function add_render_callback(fn) {
 	render_callbacks.push(fn);
 }
 
-export function nextTick(fn) {
-	if (fn) add_render_callback(fn);
+export function tick() {
 	schedule_update();
 	return update_promise;
 }
diff --git a/test/runtime/samples/lifecycle-next-tick/main.html b/test/runtime/samples/lifecycle-next-tick/main.html
index f7a889d433..0c577c20e8 100644
--- a/test/runtime/samples/lifecycle-next-tick/main.html
+++ b/test/runtime/samples/lifecycle-next-tick/main.html
@@ -1,5 +1,5 @@
 <script>
-	import { nextTick } from 'svelte';
+	import { tick } from 'svelte';
 
 	export let snapshots = [];
 
@@ -14,7 +14,7 @@
 	function log() {
 		snapshots.push(`before ${buttons[0].textContent}`);
 
-		nextTick(() => {
+		tick().then(() => {
 			snapshots.push(`after ${buttons[0].textContent}`);
 		});
 	}

From 003dfa1ddecffa81ce9610c5ffbfbd369b6e8a90 Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Wed, 30 Jan 2019 15:19:51 -0500
Subject: [PATCH 4/5] update test

---
 test/runtime/samples/lifecycle-next-tick/_config.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/runtime/samples/lifecycle-next-tick/_config.js b/test/runtime/samples/lifecycle-next-tick/_config.js
index 35a66f7a09..9ecd589d64 100644
--- a/test/runtime/samples/lifecycle-next-tick/_config.js
+++ b/test/runtime/samples/lifecycle-next-tick/_config.js
@@ -3,13 +3,13 @@ export default {
 		const buttons = target.querySelectorAll('button');
 		const click = new window.MouseEvent('click');
 
-		await buttons[0].dispatchEvent(click);
+		await (await buttons[0].dispatchEvent(click));
 		assert.deepEqual(component.snapshots, [
 			'before 0',
 			'after 1'
 		]);
 
-		await buttons[0].dispatchEvent(click);
+		await (await buttons[0].dispatchEvent(click));
 		assert.deepEqual(component.snapshots, [
 			'before 0',
 			'after 1',
@@ -17,7 +17,7 @@ export default {
 			'after 2'
 		]);
 
-		await buttons[1].dispatchEvent(click);
+		await (await buttons[1].dispatchEvent(click));
 		assert.deepEqual(component.snapshots, [
 			'before 0',
 			'after 1',

From f0c33b5cb310727911ba752046cef12004c918bf Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Wed, 30 Jan 2019 15:33:35 -0500
Subject: [PATCH 5/5] better

---
 src/internal/scheduler.js                           | 3 ++-
 test/runtime/samples/lifecycle-next-tick/_config.js | 6 +++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/internal/scheduler.js b/src/internal/scheduler.js
index 717a5c7ff4..6c62af905c 100644
--- a/src/internal/scheduler.js
+++ b/src/internal/scheduler.js
@@ -10,7 +10,8 @@ const render_callbacks = [];
 
 export function schedule_update() {
 	if (!update_promise) {
-		update_promise = Promise.resolve().then(flush);
+		update_promise = Promise.resolve();
+		update_promise.then(flush);
 	}
 }
 
diff --git a/test/runtime/samples/lifecycle-next-tick/_config.js b/test/runtime/samples/lifecycle-next-tick/_config.js
index 9ecd589d64..35a66f7a09 100644
--- a/test/runtime/samples/lifecycle-next-tick/_config.js
+++ b/test/runtime/samples/lifecycle-next-tick/_config.js
@@ -3,13 +3,13 @@ export default {
 		const buttons = target.querySelectorAll('button');
 		const click = new window.MouseEvent('click');
 
-		await (await buttons[0].dispatchEvent(click));
+		await buttons[0].dispatchEvent(click);
 		assert.deepEqual(component.snapshots, [
 			'before 0',
 			'after 1'
 		]);
 
-		await (await buttons[0].dispatchEvent(click));
+		await buttons[0].dispatchEvent(click);
 		assert.deepEqual(component.snapshots, [
 			'before 0',
 			'after 1',
@@ -17,7 +17,7 @@ export default {
 			'after 2'
 		]);
 
-		await (await buttons[1].dispatchEvent(click));
+		await buttons[1].dispatchEvent(click);
 		assert.deepEqual(component.snapshots, [
 			'before 0',
 			'after 1',