Chart Export

1/**
2 * BoldKit Chart Export — framework-agnostic chart toolbar helpers.
3 *
4 * Operates on a chart's container element, so it works regardless of the
5 * rendering engine: Recharts (SVG) and ECharts (canvas) are both handled.
6 * Consumed by the React <ChartToolbar> and the Vue <ChartToolbar>.
7 *
8 * All functions are SSR-safe: they no-op on the server.
9 */
10 
11const isBrowser = typeof window !== 'undefined' && typeof document !== 'undefined'
12 
13function triggerDownload(href: string, filename: string) {
14  const a = document.createElement('a')
15  a.href = href
16  a.download = filename
17  document.body.appendChild(a)
18  a.click()
19  a.remove()
20}
21 
22// ──────────────────────────────────────────────────────────────────
23// CSV — from the same data array you feed the chart
24// ──────────────────────────────────────────────────────────────────
25 
26/** Escape a single CSV cell per RFC 4180 (quote if it contains ,"\n). */
27function csvCell(value: unknown): string {
28  const s = value == null ? '' : String(value)
29  return /[",\n]/.test(s) ? `"${s.replace(/"/g, '""')}"` : s
30}
31 
32/**
33 * Serialize an array of row objects to a CSV string. Columns are the union
34 * of keys across all rows, in first-seen order. Pure — no DOM access.
35 */
36export function toCSV(rows: Array<Record<string, unknown>>): string {
37  if (!rows.length) return ''
38 
39  const columns: string[] = []
40  for (const row of rows) {
41    for (const key of Object.keys(row)) {
42      if (!columns.includes(key)) columns.push(key)
43    }
44  }
45 
46  const lines = [
47    columns.map(csvCell).join(','),
48    ...rows.map((row) => columns.map((col) => csvCell(row[col])).join(',')),
49  ]
50  return lines.join('\n')
51}
52 
53/**
54 * Serialize an array of row objects to CSV and download it.
55 * Columns are the union of keys across all rows, in first-seen order.
56 */
57export function downloadCSV(rows: Array<Record<string, unknown>>, filename = 'chart.csv'): void {
58  if (!isBrowser || !rows.length) return
59 
60  const blob = new Blob([toCSV(rows)], { type: 'text/csv;charset=utf-8;' })
61  const url = URL.createObjectURL(blob)
62  triggerDownload(url, filename)
63  URL.revokeObjectURL(url)
64}
65 
66// … truncated