JS cleanup (#640)

* JS cleanup

* remove unused function
* leaflet: properly clean up object URLs
* maplibre: refactor tile type detection
* update leaflet raster example

js/src/adapters.ts

@@ -77,6 +77,7 @@ export const leafletRasterLayer = (source: PMTiles, options: unknown) => {
       }
 
       if (tile.el.cancel) tile.el.cancel();
+      if (tile.el.src) window.URL.revokeObjectURL(tile.el.src);
 
       tile.el.width = 0;
       tile.el.height = 0;
@@ -256,7 +257,6 @@ export class Protocol {
     const x = result[3];
     const y = result[4];
 
-    const header = await instance.getHeader();
     const resp = await instance?.getZxy(+z, +x, +y, abortController.signal);
     abortController.signal.throwIfAborted();
     if (resp) {
@@ -266,6 +266,7 @@ export class Protocol {
         expires: resp.expires,
       };
     }
+    const header = await instance.getHeader();
     if (header.tileType === TileType.Mvt) {
       if (this.errorOnMissingTile) {
         throw new Error("Tile not found.");

js/src/index.ts

@@ -551,23 +551,6 @@ function deserializeIndex(buffer: ArrayBuffer): Entry[] {
   return entries;
 }
 
-function detectVersion(a: ArrayBuffer): number {
-  const v = new DataView(a);
-  if (v.getUint16(2, true) === 2) {
-    console.error(
-      "PMTiles spec version 2 is not supported; please see github.com/protomaps/PMTiles for tools to upgrade"
-    );
-    return 2;
-  }
-  if (v.getUint16(2, true) === 1) {
-    console.error(
-      "PMTiles spec version 1 is not supported; please see github.com/protomaps/PMTiles for tools to upgrade"
-    );
-    return 1;
-  }
-  return 3;
-}
-
 /**
  * Error thrown when a response for PMTiles over HTTP does not match previous, cached parts of the archive.
  * The default PMTiles implementation will catch this error once internally and retry a request.