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Added support for maxTimeDelta and dateFormat

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This commit is contained in:
Michal Pemcak
2025-07-19 10:37:12 +02:00
parent ac387674a4
commit 474865ddb4
6 changed files with 107 additions and 43 deletions
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102
README.md
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@@ -6,11 +6,39 @@ Lightweight, canvas‑based charting library written in TypeScript, designed for
## Features
- 💡 **Zero external rendering deps** – plain `<canvas>`
- 💡 **Zero external deps** – plain `<canvas>`
- ⚡ **Real‑time friendly** – redraws only what’s needed
- 📦 **ESM ready** – authored as native ES modules
- 📝 **TypeScript types** included (`*.d.ts`)
- 🎛️ Configurable axes, ticks, colors & cursor read‑outs
- 🎛️ Configurable axes, ticks, colors, date formatting & cursor read‑outs
## Options
The `createChartElement(seriesList, options)` function supports the following options:
| Option | Type | Description |
|------------------|-------------------------------------|-----------------------------------------------------------------------------|
| `width` | `number` | Fixed chart width in pixels (optional, defaults to container width) |
| `height` | `number` | Fixed chart height in pixels (optional, defaults to container height) |
| `min` | `number` | Minimum Y-axis value (optional, auto-computed if not set) |
| `max` | `number` | Maximum Y-axis value (optional, auto-computed if not set) |
| `showYAxis` | `boolean` | Whether to render Y-axis ticks and labels |
| `yTicks` | `number` | Number of Y-axis ticks (default: `5`) |
| `backgroundColor`| `string` | Optional background fill color |
| `maxTimeDelta` | `number \| null` | Gap in ms that breaks line continuity (default: `600`) |
| `dateFormat` | `(ts: number) => string` | Custom formatter for the cursor timestamp label |
```ts
// Example: format timestamp to full Czech date+time
dateFormat: (ts) => new Date(ts).toLocaleString('cs-CZ', {
hour: '2-digit',
minute: '2-digit',
second: '2-digit',
day: '2-digit',
month: '2-digit',
year: 'numeric'
})
```
## Installation
@@ -25,47 +53,61 @@ npm install @meteolab/uchart
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>uChart Interactive Test</title>
<style>
#chartContainer{width:1000px;height:400px;margin:20px auto;background:#111}
body{background:#222}
</style>
<meta charset="UTF-8" />
<title>uChart Interactive Test</title>
<style>
#chartContainer { width: 1000px; height: 400px; margin: 20px auto; background:#111; }
body { background:#222; }
</style>
</head>
<body>
<div id="chartContainer"></div>
<script type="module">
import { createChartElement } from './dist/uchart.js';
import { createChartElement } from './dist/uchart.js';
const container = document.getElementById('chartContainer');
const chart = createChartElement([], { showYAxis:true, yTicks:5 });
container.appendChild(chart.element);
const container = document.getElementById('chartContainer');
const chart = createChartElement([], {
showYAxis: true,
yTicks: 5,
dateFormat: (ts) => new Date(ts).toLocaleString('cs-CZ', {
hour: '2-digit',
minute: '2-digit',
second: '2-digit',
day: '2-digit',
month: '2-digit',
year: 'numeric'
})
}); container.appendChild(chart.element);
let phase = 0;
let phase = 0;
function sine(len, shift, amp, off, f=1){
const now=Date.now(), d=[];
for(let i=0;i<len;i++){
const t=now+i*10, x=i/len*2*Math.PI*f, y=Math.sin(x+shift)*amp+off;
d.push([t,y]);
function generateSineSeries(len, shift, amp, off, freq = 1){
const now = Date.now();
const data=[];
for(let i=0;i<len;i++){
const t = now + i*10;
const x = i/len*2*Math.PI*freq;
const y = Math.sin(x+shift)*amp + off;
data.push([t,y]);
}
return data;
}
return d;
}
function update(){
chart.setSeries([
{ data: sine(1500, phase, 20, 10, 1), strokeColor:'#0f0' },
{ data: sine(1500, phase, 20, 10, 2), strokeColor:'#f00' },
{ data: sine(1500, phase, 20, 10, 0.5), strokeColor:'#00f' }
]);
phase += 0.01;
}
update();
setInterval(update, 50);
function update(){
chart.setSeries([
{ data: generateSineSeries(1500, phase, 20, 10, 1), strokeColor:'#0f0' },
{ data: generateSineSeries(1500, phase, 20, 10, 2), strokeColor:'#f00' },
{ data: generateSineSeries(1500, phase, 20, 10, 0.5), strokeColor:'#00f' }
]);
phase += 0.01;
}
update()
setInterval(update, 50);
</script>
</body>
</html>
```
## Test

4
src/index.d.ts → dist/index.d.ts vendored
View File

@@ -11,6 +11,8 @@ export declare function drawChart(ctx: CanvasRenderingContext2D, seriesList: Cha
yTicks?: number;
backgroundColor?: string;
cursorX?: number | null;
maxTimeDelta?: number | null;
dateFormat?: (ts: number) => string;
}): void;
export declare function createChartElement(seriesList: ChartSeries[], opts: {
width?: number;
@@ -20,6 +22,8 @@ export declare function createChartElement(seriesList: ChartSeries[], opts: {
showYAxis?: boolean;
yTicks?: number;
backgroundColor?: string;
maxTimeDelta?: number | null;
dateFormat?: (ts: number) => string;
}): {
element: HTMLDivElement;
setSeries(series: ChartSeries[]): void;

2
dist/uchart.js vendored
View File

@@ -1 +1 @@
function W(t,m,a){let{width:o,height:d,min:F,max:n,showYAxis:T=!1,yTicks:w=5,cursorX:l=null}=a,k=10,E=d-k-10,x=m.flatMap(s=>s.data.map(i=>i[1])),y=m.flatMap(s=>s.data.map(i=>i[0])),p=F!==void 0?F:Math.min(...x),P=n!==void 0?n:Math.max(...x),e=P-p||1,r=Math.min(...y),A=Math.max(...y)-r||1;if(t.clearRect(0,0,o,d),T){t.beginPath(),t.strokeStyle="#aaa",t.lineWidth=1,t.font="15px sans-serif",t.fillStyle=m[0]?.strokeColor||"#000";for(let s=0;s<=w;s++){let i=p+e*s/w,c=k+(1-(i-p)/e)*E;t.moveTo(0,c),t.lineTo(5,c),t.fillText(i.toFixed(2),8,c+5)}t.stroke()}for(let s of m){let i=s.data,c=s.strokeColor||"#000";t.beginPath(),t.strokeStyle=c,t.lineWidth=1;let g=!1,C=null,b=600;for(let v=0;v<i.length;v++){let[h,f]=i[v];if(h==null||f==null||isNaN(h)||isNaN(f)||!isFinite(h)||!isFinite(f)||f<p||f>P){g=!1,C=null;continue}C!=null&&h-C>b&&(g=!1);let u=(h-r)/A*o,M=k+(1-(f-p)/e)*E;g?t.lineTo(u,M):(t.moveTo(u,M),g=!0),C=h}t.stroke()}if(l!==null&&l>=0&&l<=o){let s=r+l/o*A;t.beginPath(),t.strokeStyle="#888",t.lineWidth=1,t.moveTo(l,0),t.lineTo(l,d),t.stroke(),t.font="12px sans-serif";let i=15;t.fillStyle="#fff",t.fillText(new Date(s).toLocaleTimeString(),l+6,i),i+=15;for(let c of m){let{data:g,strokeColor:C="#fff"}=c,b=g[0],v=Math.abs(b[0]-s);for(let h=1;h<g.length;h++){let f=Math.abs(g[h][0]-s);f<v&&(v=f,b=g[h])}t.fillStyle=C,t.fillText(b[1].toFixed(2),l+6,i),i+=15}}}function X(t,m){let a=document.createElement("div");a.style.position="relative",a.style.width=m.width!==void 0?`${m.width}px`:"100%",a.style.height=m.height!==void 0?`${m.height}px`:"100%";let o=document.createElement("canvas"),d=document.createElement("canvas");[o,d].forEach(e=>{e.style.position="absolute",e.style.top=e.style.left="0",e.style.width=e.style.height="100%",a.appendChild(e)}),d.style.pointerEvents="none";let F=o.getContext("2d"),n=d.getContext("2d"),T=t,w={...m},l=null,k=!1,S=()=>{let e=a.clientWidth,r=a.clientHeight;!e||!r||o.width===e&&o.height===r||(o.width=e,o.height=r,d.width=e,d.height=r,x(),y(l))},E=typeof ResizeObserver<"u"?new ResizeObserver(S):null;E?.observe(a),window.addEventListener("resize",S);let x=()=>{W(F,T,{...w,width:o.width,height:o.height})},y=e=>{if(n.clearRect(0,0,d.width,d.height),e==null)return;let r=T.flatMap(u=>u.data.map(M=>M[1])),Y=T.flatMap(u=>u.data.map(M=>M[0])),A=w.min??Math.min(...r),i=(w.max??Math.max(...r))-A||1,c=Math.min(...Y),C=Math.max(...Y)-c||1,b=c+e/o.width*C;n.beginPath(),n.strokeStyle="#888",n.lineWidth=1,n.moveTo(e,0),n.lineTo(e,d.height),n.stroke(),n.font="12px sans-serif",n.fillStyle="#fff",n.fillText(new Date(b).toLocaleTimeString(),e>o.width-100?e-100:e+6,15);let v=10,f=d.height-v-10,z=30;for(let{data:u,strokeColor:M="#fff"}of T){let L=u[0],D=Math.abs(L[0]-b);for(let R=1;R<u.length;R++){let O=Math.abs(u[R][0]-b);O<D&&(D=O,L=u[R])}n.fillStyle=M,n.fillText(L[1].toFixed(2),e>o.width-100?e-100:e+6,z),z+=15;let V=v+(1-(L[1]-A)/i)*f;n.beginPath(),n.arc(e,V,3,0,Math.PI*2),n.fill()}},p=e=>{let r=a.getBoundingClientRect(),Y=o.width/r.width;l=(e.clientX-r.left)*Y,k||(k=!0,requestAnimationFrame(()=>{y(l),k=!1}))},P=()=>{l=null,y(null)};return a.addEventListener("mousemove",p),a.addEventListener("mouseleave",P),setTimeout(S,0),{element:a,setSeries(e){T=e,S(),x(),y(l)},setOptions(e){w={...w,...e},S(),x(),y(l)},destroy(){E?.disconnect(),window.removeEventListener("resize",S),a.removeEventListener("mousemove",p),a.removeEventListener("mouseleave",P)}}}export{X as createChartElement,W as drawChart};
function N(t,u,o){let{width:a,height:m,min:Y,max:n,showYAxis:x=!1,yTicks:w=5,cursorX:s=null,maxTimeDelta:P}=o,c=10,k=m-c-10,y=u.flatMap(l=>l.data.map(i=>i[1])),E=u.flatMap(l=>l.data.map(i=>i[0])),p=Y!==void 0?Y:Math.min(...y),e=n!==void 0?n:Math.max(...y),r=e-p||1,C=Math.min(...E),L=Math.max(...E)-C||1;if(t.clearRect(0,0,a,m),x){t.beginPath(),t.strokeStyle="#aaa",t.lineWidth=1,t.font="15px sans-serif",t.fillStyle=u[0]?.strokeColor||"#000";for(let l=0;l<=w;l++){let i=p+r*l/w,T=c+(1-(i-p)/r)*k;t.moveTo(0,T),t.lineTo(5,T),t.fillText(i.toFixed(2),8,T+5)}t.stroke()}for(let l of u){let i=l.data,T=l.strokeColor||"#000";t.beginPath(),t.strokeStyle=T,t.lineWidth=1;let g=!1,d=null,F=P||600;for(let b=0;b<i.length;b++){let[v,h]=i[b];if(v==null||h==null||isNaN(v)||isNaN(h)||!isFinite(v)||!isFinite(h)||h<p||h>e){g=!1,d=null;continue}d!=null&&v-d>F&&(g=!1);let f=(v-C)/L*a,M=c+(1-(h-p)/r)*k;g?t.lineTo(f,M):(t.moveTo(f,M),g=!0),d=v}t.stroke()}if(s!==null&&s>=0&&s<=a){let l=C+s/a*L;t.beginPath(),t.strokeStyle="#888",t.lineWidth=1,t.moveTo(s,0),t.lineTo(s,m),t.stroke(),t.font="12px sans-serif";let i=15;t.fillStyle="#fff";let T=o.dateFormat??(g=>new Date(g).toLocaleTimeString());t.fillText(T(l),s+6,i),i+=15;for(let g of u){let{data:d,strokeColor:F="#fff"}=g,b=d[0],v=Math.abs(b[0]-l);for(let h=1;h<d.length;h++){let S=Math.abs(d[h][0]-l);S<v&&(v=S,b=d[h])}t.fillStyle=F,t.fillText(b[1].toFixed(2),s+6,i),i+=15}}}function X(t,u){let o=document.createElement("div");o.style.position="relative",o.style.width=u.width!==void 0?`${u.width}px`:"100%",o.style.height=u.height!==void 0?`${u.height}px`:"100%";let a=document.createElement("canvas"),m=document.createElement("canvas");[a,m].forEach(e=>{e.style.position="absolute",e.style.top=e.style.left="0",e.style.width=e.style.height="100%",o.appendChild(e)}),m.style.pointerEvents="none";let Y=a.getContext("2d"),n=m.getContext("2d"),x=t,w={...u},s=null,P=!1,c=()=>{let e=o.clientWidth,r=o.clientHeight;!e||!r||a.width===e&&a.height===r||(a.width=e,a.height=r,m.width=e,m.height=r,k(),y(s))},R=typeof ResizeObserver<"u"?new ResizeObserver(c):null;R?.observe(o),window.addEventListener("resize",c);let k=()=>{N(Y,x,{...w,width:a.width,height:a.height})},y=e=>{if(n.clearRect(0,0,m.width,m.height),e==null)return;let r=x.flatMap(f=>f.data.map(M=>M[1])),C=x.flatMap(f=>f.data.map(M=>M[0])),z=w.min??Math.min(...r),l=(w.max??Math.max(...r))-z||1,i=Math.min(...C),g=Math.max(...C)-i||1,d=i+e/a.width*g;n.beginPath(),n.strokeStyle="#888",n.lineWidth=1,n.moveTo(e,0),n.lineTo(e,m.height),n.stroke(),n.font="12px sans-serif",n.fillStyle="#fff";let F=w.dateFormat??(f=>new Date(f).toLocaleTimeString());n.fillText(F(d),e>a.width-100?e-100:e+6,15);let b=10,h=m.height-b-10,S=30;for(let{data:f,strokeColor:M="#fff"}of x){let D=f[0],O=Math.abs(D[0]-d);for(let A=1;A<f.length;A++){let V=Math.abs(f[A][0]-d);V<O&&(O=V,D=f[A])}n.fillStyle=M,n.fillText(D[1].toFixed(2),e>a.width-100?e-100:e+6,S),S+=15;let W=b+(1-(D[1]-z)/l)*h;n.beginPath(),n.arc(e,W,3,0,Math.PI*2),n.fill()}},E=e=>{let r=o.getBoundingClientRect(),C=a.width/r.width;s=(e.clientX-r.left)*C,P||(P=!0,requestAnimationFrame(()=>{y(s),P=!1}))},p=()=>{s=null,y(null)};return o.addEventListener("mousemove",E),o.addEventListener("mouseleave",p),setTimeout(c,0),{element:o,setSeries(e){x=e,c(),k(),y(s)},setOptions(e){w={...w,...e},c(),k(),y(s)},destroy(){R?.disconnect(),window.removeEventListener("resize",c),o.removeEventListener("mousemove",E),o.removeEventListener("mouseleave",p)}}}export{X as createChartElement,N as drawChart};

3
package.json
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@@ -3,7 +3,7 @@
"publishConfig": {
"access": "public"
},
"version": "1.0.6",
"version": "1.0.7",
"description": "Lightweight charting library for the browser and Node.js",
"license": "MIT",
"repository": {
@@ -41,7 +41,6 @@
"serve": "npx http-server . -c-1 --gzip"
},
"dependencies": {
"axios": "^1.5.0"
},
"devDependencies": {
"esbuild": "^0.25.5",

19
src/index.ts
View File

@@ -15,6 +15,8 @@ export function drawChart(
yTicks?: number;
backgroundColor?: string;
cursorX?: number | null;
maxTimeDelta?: number | null;
dateFormat?: (ts: number) => string;
}
): void {
const {
@@ -24,7 +26,8 @@ export function drawChart(
max,
showYAxis = false,
yTicks = 5,
cursorX = null
cursorX = null,
maxTimeDelta
} = opts;
const topPadding = 10;
@@ -67,10 +70,12 @@ export function drawChart(
let penDown = false;
let lastT: number | null = null;
const MAX_TIME_DELTA = 600;
// let MAX_TIME_DELTA = 600;
let max_time_delta = maxTimeDelta || 600;
for (let i = 0; i < data.length; i++) {
const [ti, vi] = data[i];
const invalid =
ti == null ||
vi == null ||
@@ -85,7 +90,7 @@ export function drawChart(
lastT = null;
continue;
}
if (lastT != null && ti - lastT > MAX_TIME_DELTA) penDown = false;
if (lastT != null && ti - lastT > max_time_delta) penDown = false;
const x = ((ti - minX) / rangeX) * width;
const y = topPadding + (1 - (vi - minVal) / rangeY) * usableHeight;
if (!penDown) {
@@ -111,7 +116,8 @@ export function drawChart(
ctx.font = '12px sans-serif';
let textY = 15;
ctx.fillStyle = '#fff';
ctx.fillText(new Date(tAtCursor).toLocaleTimeString(), cursorX + 6, textY);
const formatTime = opts.dateFormat ?? ((ts: number) => new Date(ts).toLocaleTimeString());
ctx.fillText(formatTime(tAtCursor), cursorX + 6, textY);
textY += 15;
for (const series of seriesList) {
@@ -142,6 +148,8 @@ export function createChartElement(
showYAxis?: boolean;
yTicks?: number;
backgroundColor?: string;
maxTimeDelta?: number | null;
dateFormat?: (ts: number) => string;
}
) {
const container = document.createElement('div');
@@ -217,7 +225,8 @@ export function createChartElement(
overlayCtx.font = '12px sans-serif';
overlayCtx.fillStyle = '#fff';
overlayCtx.fillText(new Date(tAtCursor).toLocaleTimeString(), cursorX > baseCanvas.width - 100 ? cursorX - 100 : cursorX + 6, 15);
const formatTime = currentOpts.dateFormat ?? ((ts: number) => new Date(ts).toLocaleTimeString());
overlayCtx.fillText(formatTime(tAtCursor), cursorX > baseCanvas.width - 100 ? cursorX - 100 : cursorX + 6, 15);
const topPadding = 10;
const bottomPadding = 10;

14
test.html
View File

@@ -16,8 +16,18 @@
import { createChartElement } from './dist/uchart.js';
const container = document.getElementById('chartContainer');
const chart = createChartElement([], { showYAxis:true, yTicks:5 });
container.appendChild(chart.element);
const chart = createChartElement([], {
showYAxis: true,
yTicks: 5,
dateFormat: (ts) => new Date(ts).toLocaleString('cs-CZ', {
hour: '2-digit',
minute: '2-digit',
second: '2-digit',
day: '2-digit',
month: '2-digit',
year: 'numeric'
})
}); container.appendChild(chart.element);
let phase = 0;