oppi.li
source dump of claude code
1export type FpsMetrics = {
2 averageFps: number
3 low1PctFps: number
4}
5
6export class FpsTracker {
7 private frameDurations: number[] = []
8 private firstRenderTime: number | undefined
9 private lastRenderTime: number | undefined
10
11 record(durationMs: number): void {
12 const now = performance.now()
13 if (this.firstRenderTime === undefined) {
14 this.firstRenderTime = now
15 }
16 this.lastRenderTime = now
17 this.frameDurations.push(durationMs)
18 }
19
20 getMetrics(): FpsMetrics | undefined {
21 if (
22 this.frameDurations.length === 0 ||
23 this.firstRenderTime === undefined ||
24 this.lastRenderTime === undefined
25 ) {
26 return undefined
27 }
28
29 const totalTimeMs = this.lastRenderTime - this.firstRenderTime
30 if (totalTimeMs <= 0) {
31 return undefined
32 }
33
34 const totalFrames = this.frameDurations.length
35 const averageFps = totalFrames / (totalTimeMs / 1000)
36
37 const sorted = this.frameDurations.slice().sort((a, b) => b - a)
38 const p99Index = Math.max(0, Math.ceil(sorted.length * 0.01) - 1)
39 const p99FrameTimeMs = sorted[p99Index]!
40 const low1PctFps = p99FrameTimeMs > 0 ? 1000 / p99FrameTimeMs : 0
41
42 return {
43 averageFps: Math.round(averageFps * 100) / 100,
44 low1PctFps: Math.round(low1PctFps * 100) / 100,
45 }
46 }
47}