``` ### `src/components/viewership/insight-cards/insight-chart.ts` ```ts /** * insight-chart: types and chart maths for . * * Ported from Beautiful UI `components/primitives/InsightCards.tsx` * (MIT, © 2026 Shane Levine). Native SVG line chart: Catmull-Rom * smoothing, paths, grid ticks, value formatting and a text summary. No DOM * access, so server render and client script share it. */ export type Tone = "red" | "green"; /** Prose is a list of tokens: plain strings, @entities, mono deltas and emphasis. */ export interface ProseEntity { entity: string; /** Dot color, any CSS color. */ color?: string; } export interface ProseMono { mono: string; tone: Tone; } export interface ProseStrong { strong: string; } export type ProseToken = string | ProseEntity | ProseMono | ProseStrong; export interface ValueFormat { style: "percent" | "money" | "unit"; /** Suffix for style "unit", e.g. "clicks". */ unit?: string; /** Fraction digits (percent defaults to 2, others to 0). */ decimals?: number; /** Prefix positive values with "+" (percent defaults to true). */ signed?: boolean; /** Currency symbol for style "money". Default "$". */ currency?: string; } export interface CompareSeries { name: string; values: number[]; /** Mono sub-line under the big value, e.g. "-$2,377.66". */ sub: string; tone: Tone; /** Line color, any CSS color. */ color: string; } export interface CompareCard { kind: "compare"; /** Chart toolbar caption. */ caption?: string; badge?: string; series: CompareSeries[]; format?: ValueFormat; /** X-axis labels, one per value (first, middle and last are shown). */ labels?: string[]; } export interface AnomalyMetric { key: string; label: string; values: number[]; format: ValueFormat; /** Shown in the chart toolbar when not scrubbing, e.g. "$2,112 threshold". */ threshold: string; } export interface AnomalyCard { kind: "anomaly"; title: string; badge?: string; metrics: AnomalyMetric[]; /** Line color. Default var(--vs-red). */ color?: string; /** Footer: big value, mono delta and a note. */ total: string; delta: string; deltaTone?: Tone; deltaNote: string; labels?: string[]; } export interface AllocationSegment { name: string; label: string; pct: number; amount: string; /** Segment fill, any CSS color. */ color: string; /** Label color in the detail box (defaults to `color`). */ tone?: string; } export interface AllocationCard { kind: "allocation"; title: string; monogram?: string; /** Monogram disc color. */ color?: string; segments: AllocationSegment[]; note: string; } export type InsightCard = CompareCard | AnomalyCard | AllocationCard; export interface InsightPage { key: string; prose: ProseToken[]; card: InsightCard; /** Suggested follow-up shown as a pill button. */ pill?: string; } /* ── maths ─────────────────────────────────────────────── */ export const SAMPLES_PER_SEGMENT = 9; export const VIEW_W = 1000; /** Catmull-Rom resample: a sparse series becomes a dense, smoothly curved one. */ export function smooth(values: number[], perSegment = SAMPLES_PER_SEGMENT): number[] { if (values.length < 3) return values.slice(); const out: number[] = []; const n = values.length; for (let i = 0; i < n - 1; i += 1) { const p0 = values[Math.max(0, i - 1)]; const p1 = values[i]; const p2 = values[i + 1]; const p3 = values[Math.min(n - 1, i + 2)]; for (let s = 0; s < perSegment; s += 1) { const t = s / perSegment; const t2 = t * t; const t3 = t2 * t; out.push(0.5 * (2 * p1 + (-p0 + p2) * t + (2 * p0 - 5 * p1 + 4 * p2 - p3) * t2 + (-p0 + 3 * p1 - 3 * p2 + p3) * t3)); } } out.push(values[n - 1]); return out; } export interface Box { height: number; top: number; bottom: number; } /** Plot boxes (px in the 1000x166 viewBox); must match the viewBox in InsightCards.astro. */ export const COMPARE_BOX: Box = { height: 166, top: 40, bottom: 22 }; export const ANOMALY_BOX: Box = { height: 166, top: 34, bottom: 22 }; export function domain(series: number[][]): [number, number] { const all = series.flat(); let min = Math.min(...all); let max = Math.max(...all); if (!Number.isFinite(min) || !Number.isFinite(max)) return [0, 1]; if (min === max) { min -= 1; max += 1; } const pad = (max - min) * 0.06; return [min - pad, max + pad]; } export function yOf(value: number, [min, max]: [number, number], box: Box): number { const plot = box.height - box.top - box.bottom; return box.top + (1 - (value - min) / (max - min)) * plot; } /** SVG path for a dense series across the full view width. */ export function linePath(dense: number[], dom: [number, number], box: Box): string { if (!dense.length) return ""; const step = dense.length > 1 ? VIEW_W / (dense.length - 1) : 0; return dense.map((v, i) => `${i ? "L" : "M"}${(i * step).toFixed(1)},${yOf(v, dom, box).toFixed(1)}`).join(""); } export function areaPath(dense: number[], dom: [number, number], box: Box): string { const line = linePath(dense, dom, box); return line ? `${line}L${VIEW_W},${box.height}L0,${box.height}Z` : ""; } /** About `count` round tick values inside the domain. */ export function niceTicks([min, max]: [number, number], count = 3): number[] { const raw = (max - min) / (count + 1); const mag = 10 ** Math.floor(Math.log10(raw)); const norm = raw / mag; const step = (norm >= 5 ? 5 : norm >= 2 ? 2 : 1) * mag; const ticks: number[] = []; for (let v = Math.ceil(min / step) * step; v <= max; v += step) ticks.push(Number(v.toFixed(10))); return ticks; } export function formatValue(value: number, f: ValueFormat = { style: "percent" }): string { const decimals = f.decimals ?? (f.style === "percent" ? 2 : 0); const signed = f.signed ?? f.style === "percent"; const abs = Math.abs(value).toLocaleString("en-US", { minimumFractionDigits: decimals, maximumFractionDigits: decimals }); const sign = value < 0 ? "-" : signed && value > 0 ? "+" : ""; if (f.style === "percent") return `${sign}${abs}%`; if (f.style === "money") return `${sign}${f.currency ?? "$"}${abs}`; return `${sign}${abs}${f.unit ? ` ${f.unit}` : ""}`; } /** Plain-language chart summary for assistive tech. */ export function summarize(series: Array<{ name: string; values: number[] }>, f: ValueFormat, labels?: string[]): string { const span = labels?.length ? ` from ${labels[0]} to ${labels[labels.length - 1]}` : ` over ${series[0]?.values.length ?? 0} readings`; const parts = series.map((s) => { const first = s.values[0] ?? 0; const last = s.values[s.values.length - 1] ?? 0; const peak = Math.max(...s.values); const low = Math.min(...s.values); const dir = last > first ? "rose" : last < first ? "fell" : "held"; return `${s.name} ${dir} from ${formatValue(first, f)} to ${formatValue(last, f)} (high ${formatValue(peak, f)}, low ${formatValue(low, f)})`; }); return `Line chart${span}. ${parts.join("; ")}.`; } ```