From b89e611a94d34e4c43666e5301190f76e473941b Mon Sep 17 00:00:00 2001
From: unknown <robertadamsonsmith@gmail.com>
Date: Mon, 13 Dec 2021 00:23:17 +0000
Subject: [PATCH 1/2] Initial commit

---
 src/runtime/motion/spring.ts | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/runtime/motion/spring.ts b/src/runtime/motion/spring.ts
index 64d17a058b26..d85bc3ae30cc 100644
--- a/src/runtime/motion/spring.ts
+++ b/src/runtime/motion/spring.ts
@@ -49,6 +49,8 @@ interface SpringOpts {
 	stiffness?: number;
 	damping?: number;
 	precision?: number;
+	tick?: number;
+	limit?: number;
 }
 
 interface SpringUpdateOpts {
@@ -64,11 +66,13 @@ export interface Spring<T> extends Readable<T>{
 	precision: number;
 	damping: number;
 	stiffness: number;
+	tick: number;
+	limit: number;
 }
 
 export function spring<T=any>(value?: T, opts: SpringOpts = {}): Spring<T> {
 	const store = writable(value);
-	const { stiffness = 0.15, damping = 0.8, precision = 0.01 } = opts;
+	const { stiffness = 0.15, damping = 0.8, precision = 0.01, tick = 16, limit = 30 } = opts;
 
 	let last_time: number;
 	let task: Task;
@@ -110,22 +114,31 @@ export function spring<T=any>(value?: T, opts: SpringOpts = {}): Spring<T> {
 
 				inv_mass = Math.min(inv_mass + inv_mass_recovery_rate, 1);
 
+				last_time = Math.max(last_time, now - tick * limit);
+				while ( last_time < now ) {
+					const elapsed = Math.min(tick, now - last_time);
+					last_time += elapsed;
+
 				const ctx: TickContext<T> = {
 					inv_mass,
 					opts: spring,
 					settled: true, // tick_spring may signal false
-					dt: (now - last_time) * 60 / 1000
+					dt: elapsed * 60 / 1000
 				};
 				const next_value = tick_spring(ctx, last_value, value, target_value);
 
 				last_time = now;
 				last_value = value;
-				store.set(value = next_value);
+				value = next_value;
 
 				if (ctx.settled) {
 					task = null;
+					store.set(value);				
+					return false;
+				}
 				}
-				return !ctx.settled;
+				store.set(value);				
+				return true;
 			});
 		}
 
@@ -142,7 +155,9 @@ export function spring<T=any>(value?: T, opts: SpringOpts = {}): Spring<T> {
 		subscribe: store.subscribe,
 		stiffness,
 		damping,
-		precision
+		precision,
+		tick,
+		limit
 	};
 
 	return spring;

From 8ccfa7f53226453abe2c66e8298d0de9063cd7a9 Mon Sep 17 00:00:00 2001
From: Rich Harris <hello@rich-harris.dev>
Date: Thu, 30 Mar 2023 17:24:14 -0400
Subject: [PATCH 2/2] Update src/runtime/motion/spring.ts

Co-authored-by: Ben McCann <322311+benmccann@users.noreply.github.com>
---
 src/runtime/motion/spring.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/runtime/motion/spring.ts b/src/runtime/motion/spring.ts
index d85bc3ae30cc..ce93646dcca8 100644
--- a/src/runtime/motion/spring.ts
+++ b/src/runtime/motion/spring.ts
@@ -115,7 +115,7 @@ export function spring<T=any>(value?: T, opts: SpringOpts = {}): Spring<T> {
 				inv_mass = Math.min(inv_mass + inv_mass_recovery_rate, 1);
 
 				last_time = Math.max(last_time, now - tick * limit);
-				while ( last_time < now ) {
+				while (last_time < now) {
 					const elapsed = Math.min(tick, now - last_time);
 					last_time += elapsed;