maplibre: cancel correctly captued in closure [#6]

js/index.src.mjs

@@ -212,16 +212,18 @@ export const addProtocol = maplibre_instance => {
                 let headers = {'Range':'bytes=' + val[0] + '-' + (val[0]+val[1]-1)}
                 const controller = new AbortController()
                 const signal = controller.signal
+                cancel = () => { controller.abort() }
                 fetch(pmtiles_url,{signal:signal,headers:headers}).then(resp => {
                     return resp.arrayBuffer()
                 }).then(arr => {
                     callback(null,arr,null,null)
+                }).catch(e => {
+                    callback(new Error("Canceled"),null,null,null)
                 })
-                cancel = controller.abort
             } else {
                 callback(null,new Uint8Array(),null,null)
             }
         })
-        return { cancel: cancel }
+        return { cancel: () => { cancel() } }
      })
 }