From 610574c23ae44f95b7b0326e4456e17a6a68a2a0 Mon Sep 17 00:00:00 2001
From: Alexander Zinchuk <alx.zinchuk@gmail.com>
Date: Sun, 13 Nov 2022 17:05:44 +0400
Subject: [PATCH] [Perf] Fix slow `animate` function

---
 src/util/FrameDebugger.ts              | 99 ++++++++++++++++++++++++++
 src/util/animation.ts                  | 12 +++-
 src/util/fastSmoothScrollHorizontal.ts | 27 ++++---
 3 files changed, 121 insertions(+), 17 deletions(-)
 create mode 100644 src/util/FrameDebugger.ts

diff --git a/src/util/FrameDebugger.ts b/src/util/FrameDebugger.ts
new file mode 100644
index 000000000..fac14a617
--- /dev/null
+++ b/src/util/FrameDebugger.ts
@@ -0,0 +1,99 @@
+const RANDOM = 0.95;
+const DEBOUNCE = 3000;
+
+export default class FrameDebugger {
+  private durations: number[] = [];
+
+  private startedAtByFrameKey: Record<string, number | undefined> = {};
+
+  private passedFrames: string[] = [];
+
+  private timeout: number | undefined;
+
+  constructor(private name: string = '[No name]') {
+  }
+
+  onFrameStart(frameKey = '0') {
+    if (this.passedFrames.includes(frameKey)) {
+      // debugger
+    }
+
+    if (this.startedAtByFrameKey[frameKey]) {
+      return;
+    }
+
+    this.startedAtByFrameKey[frameKey] = performance.now();
+  }
+
+  onFrameEnd(frameKey = '0', onAnimationEnd?: AnyToVoidFunction) {
+    if (!this.startedAtByFrameKey[frameKey]) {
+      return;
+    }
+
+    const duration = performance.now() - this.startedAtByFrameKey[frameKey]!;
+
+    if (this.passedFrames.includes(frameKey)) {
+      // debugger
+    }
+
+    this.passedFrames.push(frameKey);
+    this.durations.push(duration);
+
+    this.startedAtByFrameKey[frameKey] = undefined;
+
+    if (Math.random() < RANDOM) {
+      return;
+    }
+
+    if (this.timeout) {
+      clearTimeout(this.timeout);
+    }
+
+    // eslint-disable-next-line no-restricted-globals
+    this.timeout = self.setTimeout(() => {
+      if (!this.durations.length) {
+        return;
+      }
+
+      const max = Math.max(...this.durations);
+      const min = Math.max(...this.durations);
+      const maxIndex = this.durations.indexOf(max);
+      const minIndex = this.durations.indexOf(min);
+      const reduced = this.durations.slice();
+      reduced.splice(maxIndex, 1);
+      reduced.splice(minIndex, 1);
+      const avg = reduced.reduce((acc, cur) => acc + cur, 0) / this.durations.length;
+
+      // eslint-disable-next-line no-console
+      console.log(
+        '!!!',
+        this.name,
+        'total frames:',
+        this.durations.length,
+        ', avg duration:',
+        avg.toFixed(2),
+        ', max duration:',
+        Math.max(...reduced).toFixed(2),
+        ', min duration:',
+        Math.min(...reduced).toFixed(2),
+      );
+
+      onAnimationEnd?.();
+
+      this.reset();
+    }, DEBOUNCE);
+  }
+
+  reset() {
+    this.durations = [];
+
+    this.startedAtByFrameKey = {};
+
+    this.passedFrames = [];
+
+    if (this.timeout) {
+      clearTimeout(this.timeout);
+      this.timeout = undefined;
+    }
+  }
+}
diff --git a/src/util/animation.ts b/src/util/animation.ts
index c7c21d9b2..2889e360e 100644
--- a/src/util/animation.ts
+++ b/src/util/animation.ts
@@ -24,9 +24,17 @@ export function animateSingle(tick: Function, instance?: AnimationInstance) {
 }
 
 export function animate(tick: Function) {
+  fastRaf(() => {
+    if (tick()) {
+      animate(tick);
+    }
+  });
+}
+
+export function animateInstantly(tick: Function) {
   if (tick()) {
     fastRaf(() => {
-      animate(tick);
+      animateInstantly(tick);
     });
   }
 }
@@ -72,7 +80,7 @@ export function animateNumber({
   const t0 = Date.now();
   let canceled = false;
 
-  animate(() => {
+  animateInstantly(() => {
     if (canceled) return false;
     const t1 = Date.now();
     let t = (t1 - t0) / duration;
diff --git a/src/util/fastSmoothScrollHorizontal.ts b/src/util/fastSmoothScrollHorizontal.ts
index 0d7c5c210..30ae9d5db 100644
--- a/src/util/fastSmoothScrollHorizontal.ts
+++ b/src/util/fastSmoothScrollHorizontal.ts
@@ -2,7 +2,6 @@ import { getGlobal } from '../global';
 
 import { ANIMATION_LEVEL_MIN } from '../config';
 import { animate } from './animation';
-import { fastRaf } from './schedulers';
 
 const DEFAULT_DURATION = 300;
 
@@ -62,23 +61,21 @@ function scrollWithJs(container: HTMLElement, left: number, duration: number) {
   });
   const startAt = Date.now();
 
-  fastRaf(() => {
-    animate(() => {
-      if (isStopped) return false;
+  animate(() => {
+    if (isStopped) return false;
 
-      const t = Math.min((Date.now() - startAt) / duration, 1);
+    const t = Math.min((Date.now() - startAt) / duration, 1);
 
-      const currentPath = path * (1 - transition(t));
-      container.scrollLeft = Math.round(target - currentPath);
+    const currentPath = path * (1 - transition(t));
+    container.scrollLeft = Math.round(target - currentPath);
 
-      if (t >= 1) {
-        container.style.scrollSnapType = '';
-        container.dataset.scrollId = undefined;
-        stopById.delete(id);
-        resolve();
-      }
-      return t < 1;
-    });
+    if (t >= 1) {
+      container.style.scrollSnapType = '';
+      container.dataset.scrollId = undefined;
+      stopById.delete(id);
+      resolve();
+    }
+    return t < 1;
   });
 
   return promise;