Performance and large datasets

• Pre-filter candidate coordinates against turf.bbox before calling booleanPointInPolygon on complex polygons.
• Run expensive turf.buffer or turf.intersect calls inside a Worker via importScripts of turf.min.js.
• Use mutate: true to skip deep copies when the source data will not be reused.

var zone = turf.polygon([/* 上百个顶点 */]);
var box  = turf.bbox(zone);        // [西, 南, 东, 北]

function inBox(lng, lat) {
  return lng >= box[0] && lng <= box[2] &&
         lat >= box[1] && lat <= box[3];
}

var candidates = [];
turf.coordEach(pointsFC, function (coord) {
  if (inBox(coord[0], coord[1])) candidates.push(coord);
});

var hits = [];
for (var i = 0; i < candidates.length; i++) {
  if (turf.booleanPointInPolygon(candidates[i], zone)) {
    hits.push(candidates[i]);
  }
}

console.log('候选', candidates.length, '命中', hits.length);

var worker = new Worker('geo-worker.js');

worker.onmessage = function (e) {
  if (e.data.type === 'buffer') {
    map.getSource('zone').setData(e.data.result);
  }
};

worker.postMessage({
  type: 'buffer',
  center: [116.391263, 39.907359],
  radiusKm: 1.2
});
importScripts('https://cdn.jsdelivr.net/npm/@turf/turf@7/turf.min.js');

self.onmessage = function (e) {
  var msg = e.data;
  if (msg.type !== 'buffer') return;

  var pt = turf.point(msg.center);
  var zone = turf.buffer(pt, msg.radiusKm, { units: 'kilometers' });

  self.postMessage({ type: 'buffer', result: zone });
};

• Calling turf functions inside map.on('mousemove') or animation loops drops frame rates to single digits.
• Batched results must be null-checked, since some intersect calls return null and others return GeometryCollection.