Method _loadTileAsync

modules/services/VectorTileService.js:265–307

* _loadTileAsync * @param source * @param tile * @return {Promise} returns the fetch promise

(source, tile)

   * @return  {Promise} returns the fetch promise
   */
  _loadTileAsync(source, tile) {
    const tileID = tile.id;
    if (source.loaded.has(tileID) || source.inflight.has(tileID)) return;

    const controller = new AbortController();
    source.inflight.set(tileID, controller);

    const [x, y, z] = tile.xyz;
    let _fetch;

    if (source.pmtiles) {
      _fetch = source.pmtiles
        .getZxy(z, x, y, controller.signal)
        .then(response => response?.data);

    } else {
      const url = source.template
        .replace('{x}', x)
        .replace('{y}', y)
        .replace(/\{[t-]y\}/, Math.pow(2, z) - y - 1)  // TMS-flipped y coordinate
        .replace(/\{z(oom)?\}/, z)
        .replace(/\{switch:([^}]+)\}/, function(s, r) {
          const subdomains = r.split(',');
          return subdomains[(x + y) % subdomains.length];
        });

      _fetch = fetch(url, { signal: controller.signal })
        .then(utilFetchResponse);
    }

    return _fetch
      .then(buffer => {
        source.loaded.set(tileID, tile);
        this._parseTileBuffer(source, tile, buffer);
      })
      .catch(err => {
        if (err.name === 'AbortError') return;          // ok
        if (err instanceof Error) console.error(err);   // eslint-disable-line no-console
      })
      .finally(() => {
        source.inflight.delete(tileID);
      });
  }


  /**