Function fetchOverlayData

src/components/WorldMap.tsx:213–222

(layer: OverlayLayer)

// All overlay data is fetched via the local Next.js proxy (/api/overlay?layer=X)
// which handles external API calls server-side, bypassing the browser CSP connect-src policy.
async function fetchOverlayData(layer: OverlayLayer): Promise<GeoJSON.FeatureCollection> {
  try {
    const res = await fetch(`/api/overlay?layer=${layer}`);
    if (!res.ok) throw new Error(`overlay proxy ${res.status}`);
    return res.json() as Promise<GeoJSON.FeatureCollection>;
  } catch (err) {
    console.error(`[overlay] fetch failed for "${layer}":`, err);
    return { type: "FeatureCollection", features: [] };
  }
}

function WorldMapInner({
  markets,