File size: 1,580 Bytes
3e05655 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | import { expect, test } from "bun:test"
import { compressCachedRepaintTrace, layoutShiftSample } from "../timeline/session-tab-repaint-probe"
test("compresses repeated repaint states without losing frame samples", () => {
const state = {
root: 1,
scrollTop: 10,
scrollHeight: 20,
bottomErrorPx: 0,
last: true,
rows: [{ key: "row", node: 2, top: 0, bottom: 10 }],
mounted: 1,
center: "content",
}
const trace = {
timeOriginEpochMs: 1_000,
startedAtPerformanceMs: 100,
samples: [
{ observedAtMs: 16, ...state, destination: ["target"], source: [] },
{ observedAtMs: 32, ...state, destination: ["target"], source: [] },
{ observedAtMs: 48, ...state, scrollTop: 11, destination: ["target"], source: [] },
],
mutations: [{ observedAtMs: 20, changed: [{ type: "add", node: 2 }] }],
shifts: [{ occurredAtMs: 24, value: 0.1 }],
windowMs: 1_000,
running: false,
stop() {},
}
const compressed = compressCachedRepaintTrace(trace)
const samples = compressed.samples.flatMap((group) =>
group.observedAtMs.map((observedAtMs) => ({ observedAtMs, ...group.state })),
)
expect(samples).toEqual(trace.samples)
expect(compressed.mutations).toEqual(trace.mutations)
expect(compressed.shifts).toEqual(trace.shifts)
})
test("records layout shifts at occurrence time within the probe window", () => {
expect(layoutShiftSample({ startTime: 99, value: 0.1 }, 100)).toBeUndefined()
expect(layoutShiftSample({ startTime: 124, value: 0.2 }, 100)).toEqual({ occurredAtMs: 24, value: 0.2 })
})
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