Function fetchJSON

web/rusense/app/lib.js:38–50

(url, opts = {})

/** Fetch JSON with a short timeout; returns null on any failure. */
export async function fetchJSON(url, opts = {}) {
  const ctrl = new AbortController();
  const t = setTimeout(() => ctrl.abort(), opts.timeout ?? 6000);
  try {
    const res = await fetch(url, { signal: ctrl.signal, ...opts });
    if (!res.ok) return null;
    return await res.json();
  } catch {
    return null;
  } finally {
    clearTimeout(t);
  }
}

export const fmt = {
  pct: (v, d = 0) => (v == null || isNaN(v) ? '—' : `${(v * (v <= 1 ? 100 : 1)).toFixed(d)}%`),