Live line is a production-ready charts component from BJORK UI, packaged for shadcn registries.
"use client";
import { useCallback, useEffect, useRef, useState } from "react";
import { LiveLine, createRandomWalk, type LivePoint } from "@/components/ui/bjork-live-line";
import { mulberry32 } from "@/components/ui/bjork-live-line-utils/components-bjork-ui-_core-random";
const T0 = 1_700_000_000_000;
const SAMPLE_MS = 250;
const MAX_SAMPLES = 1500;
function sampleSpike(rnd: () => number, v: number): number {
return rnd() < 0.012 ? v + 70 : v;
}
function seedHistory(seed: number, end: number, spanMs: number): LivePoint[] {
const walk = createRandomWalk(seed, { base: 180, volatility: 4, hz: 4 });
const rnd = mulberry32(seed + 17);
const out: LivePoint[] = [];
for (let t = end - spanMs; t <= end; t += SAMPLE_MS) {
out.push({ t, v: sampleSpike(rnd, walk.next(t).v) });
}
return out;
}
const PREVIEW_HISTORY = seedHistory(3, T0, 60000);
const THRESHOLD = { value: 250, label: "SLO 250ms" };
const formatDemoValue = (v: number) => `${Math.round(v)} ms`;
function LiveDemo({
isPreview,
windowMs,
easing,
paused,
onPausedChange,
onRegisterControls,
}: {
isPreview: boolean;
windowMs: number;
easing: number;
paused: boolean;
onPausedChange: (paused: boolean) => void;
onRegisterControls: (controls: { injectSpike: () => void }) => void;
}) {
const [live, setLive] = useState<LivePoint[]>(PREVIEW_HISTORY);
const nextT = useRef(T0);
// Live stream at 4Hz. Pure timestamps on the synthetic clock, so nothing here reads Date.now().
useEffect(() => {
if (isPreview) return;
const walk = createRandomWalk(3, { base: 180, volatility: 4, hz: 4 });
const rnd = mulberry32(20);
const id = setInterval(() => {
nextT.current += SAMPLE_MS;
const t = nextT.current;
const v = sampleSpike(rnd, walk.next(t).v);
setLive((prev) => [...prev, { t, v }].slice(-MAX_SAMPLES));
}, SAMPLE_MS);
return () => clearInterval(id);
}, [isPreview]);
useEffect(() => {
onRegisterControls({
injectSpike: () => {
nextT.current += SAMPLE_MS;
const t = nextT.current;
setLive((prev) => [...prev, { t, v: (prev[prev.length - 1]?.v ?? 180) + 140 }].slice(-MAX_SAMPLES));
},
});
}, [onRegisterControls]);
return (
<LiveLine
data={isPreview ? PREVIEW_HISTORY : live}
window={windowMs}
easing={easing}
paused={isPreview ? true : paused}
showPauseButton={!isPreview}
onPausedChange={onPausedChange}
threshold={THRESHOLD}
formatValue={formatDemoValue}
scrub
ariaLabel="p95 latency"
/>
);
}
function SourceDemo(){
const isPreview = false;
const [windowMs, setWindowMs] = useState(60000);
const [easing, setEasing] = useState(0.08);
const [paused, setPaused] = useState(false);
const spikeRef = useRef<() => void>(() => {});
const registerControls = useCallback((c: { injectSpike: () => void }) => {
spikeRef.current = c.injectSpike;
}, []);
const reset = () => {
setWindowMs(60000);
setEasing(0.08);
setPaused(false);
};
return <>
<div className="flex w-full min-w-0 flex-col gap-5">
<LiveDemo
isPreview={isPreview}
windowMs={windowMs}
easing={easing}
paused={paused}
onPausedChange={setPaused}
onRegisterControls={registerControls}
/>
</div>
</>;
}
export default function BjorkRegistryPreview(){return <div data-component-demo className="dark flex min-h-screen w-full items-center justify-center bg-[var(--bjork-bg)] p-8 text-[var(--bjork-text)]"><div className="w-full max-w-[850px]"><SourceDemo/></div></div>}