mapbox-fitbounds-filtered-polygon-features.ts

      const map = new mapboxgl.Map(mergedOptions)
      map.on("style.load", function () {
        map.setFilter("layer-with-polygons", [
          "==",
          ["get", "City"],
          "Budapest",
        ])
      })
      map.on("load", () => {
        let features = map.querySourceFeatures("composite", {
          sourceLayer: "layer-with-polygons",
        })

        let bounds = new mapboxgl.LngLatBounds()

        features.forEach((feature) =>
          // @ts-ignore
          feature.geometry.coordinates.flat().forEach((cord: any) => bounds.extend(cord))
        )

        map.fitBounds(bounds)
      })