try some webworkers

no measurable benefit but maybe useful in the future

creates random hangs, just don't use it for the time being

some minor loading order adjustments that bring planes on the screen a
bit faster

html/early.js

@@ -583,16 +583,54 @@ function get_history() {
     }
     historyQueued.resolve();
 }
+function handleJsonWorker(e) {
+    const url = e.data.url;
+    //console.log("url finished: " + url);
+    const defer = g.jwr[url];
+    delete g.jwr[url];
+
+    defer.resolve(e.data.json);
+};
+
+function jsonGetWorker(url) {
+    const defer = jQuery.Deferred();
+    g.jwr[url] = defer;
+    const wid = g.jsonGetId++ % g.jsonWorker.length;
+    //console.log(`using worker ${wid}`);
+    g.jsonWorker[wid].postMessage(url);
+
+    return defer;
+}
+
+g.jWorkers = 0;
+if (g.jWorkers) {
+    g.jwr = {};
+
+    g.jsonWorker = [];
+    g.jsonGetId = 0;
+
+    for (let i = 0; i < g.jWorkers; i++) {
+        const worker = new Worker("jsonWorker.js");
+        g.jsonWorker.push(worker);
+        worker.onmessage = handleJsonWorker;
+    }
+
+}
 
 function get_history_item(i) {
     let request;
 
     if (HistoryChunks) {
-        let filename = chunkNames[i];
-        request = jQuery.ajax({ url: 'chunks/' + filename,
-            timeout: historyTimeout * 1000,
-            dataType: 'json'
-        });
+        const url = 'chunks/' + chunkNames[i];
+
+        if (g.jWorkers) {
+            request = jsonGetWorker(url);
+        } else {
+            request = jQuery.ajax({ url: url,
+                timeout: historyTimeout * 1000,
+                dataType: 'json'
+            });
+        }
     } else {
 
         request = jQuery.ajax({ url: 'data/history_' + i + '.json',
@@ -608,6 +646,7 @@ function get_history_item(i) {
         .fail(function(jqxhr, status, error) {
             jQuery("#loader_progress").attr('value',++HistoryItemsLoaded);
         });
+
     deferHistory.push(request);
 }
 

html/jsonWorker.js

@@ -0,0 +1,15 @@
+
+onmessage = (e) => {
+    const url = e.data;
+    fetch(new Request(url))
+        .then((response) => {
+            if (!response.ok) {
+                throw new Error(`HTTP error! Status: ${response.status} ${response.url}`);
+            }
+            return response.json();
+        })
+        .then((data) => {
+            //console.log("worker posting data with url: " + url);
+            postMessage({ url: url, json: data });
+        })
+};

html/layers.js

@@ -22,7 +22,7 @@ function createBaseLayers() {
     let us = new ol.Collection();
     let europe = new ol.Collection();
 
-    const tileTransition = onMobile ? 0 : 150;
+    const tileTransition = onMobile ? 0 : 0;
 
     if (loStore['customTiles'] != undefined) {
         custom_layers.push(new ol.layer.Tile({

html/script.js

@@ -508,7 +508,7 @@ function afterFirstFetch() {
         }
 
         console.timeEnd('afterFirstFetch()');
-    }, 150);
+    }, 50);
 }
 
 let debugFetch = false;
@@ -720,29 +720,32 @@ function initialize() {
 
         processQueryToggles();
 
-        jQuery.when(historyQueued).done(push_history);
-
-        if (nHistoryItems) {
-            jQuery.when(historyLoaded).done(afterHistoryLoad);
-        } else {
-            afterHistoryLoad();
-        }
+        tryStartPage();
     });
 }
-function afterHistoryLoad() {
-    if (!heatmap)
-        jQuery("#loader").hide();
 
-    if (!zstdDecode) {
+function doHistory() {
+
+    jQuery.when(historyQueued).done(push_history);
+
+    if (nHistoryItems) {
+        jQuery.when(historyLoaded).done(startPage);
+    } else {
         startPage();
+    }
+}
+
+function tryStartPage() {
+    if (!zstdDecode) {
+        doHistory();
     } else {
         try {
             zstddec.promise.then(function() {
-                startPage();
+                doHistory();
             });
         } catch (e) {
             webAssemblyFail(e);
-            startPage();
+            doHistory();
         }
     }
 }
@@ -1670,6 +1673,29 @@ jQuery('#selected_altitude_geom1')
         jQuery('#imageConfigLink').text(imageConfigText)
         jQuery('#imageConfigHeader').show();
     }
+
+
+    if (!globeIndex) {
+        jQuery("#lastLeg_cb").parent().hide();
+        jQuery('#show_trace').hide();
+    }
+    if (globeIndex) {
+        toggleTableInView('enable');
+        if (icaoFilter) {
+            toggleTableInView('disable');
+        }
+    } else {
+        jQuery('#V').show();
+    }
+
+    if (hideButtons) {
+        jQuery('#header_top').hide();
+        jQuery('#header_side').hide();
+        jQuery('#tabs').hide();
+        jQuery('#filterButton').hide();
+        jQuery('.ol-control').hide();
+        jQuery('.ol-attribution').show();
+    }
 }
 
 function initLegend(colors) {
@@ -1909,8 +1935,6 @@ function parseHistory() {
                 plane.last_message_time -= 999;
             }
         }
-        refreshFeatures();
-        TAR.planeMan.refresh();
     }
 
     console.timeEnd("Loaded aircraft tracks from History");
@@ -1982,7 +2006,7 @@ function setIntervalTimers() {
     }
     if (receiverJson && receiverJson.outlineJson) {
         timers.drawOutline = window.setInterval(drawOutlineJson, actualOutline.refresh);
-        drawOutlineJson();
+        setTimeout(drawOutlineJson, 50);
     }
 
     if (aiscatcher_server) {
@@ -2003,7 +2027,12 @@ function setIntervalTimers() {
     }
 
     timersActive = true;
-    fetchData();
+
+    setTimeout(fetchData, 5);
+
+    updateVisible();
+    mapRefresh();
+
     // in case the visibility changed while this was running
     handleVisibilityChange();
 }
@@ -2013,28 +2042,8 @@ let dstring;
 let dresult;
 
 function startPage() {
-
-    if (!globeIndex) {
-        jQuery("#lastLeg_cb").parent().hide();
-        jQuery('#show_trace').hide();
-    }
-    if (globeIndex) {
-        toggleTableInView('enable');
-        if (icaoFilter) {
-            toggleTableInView('disable');
-        }
-    } else {
-        jQuery('#V').show();
-    }
-
-    if (hideButtons) {
-        jQuery('#header_top').hide();
-        jQuery('#header_side').hide();
-        jQuery('#tabs').hide();
-        jQuery('#filterButton').hide();
-        jQuery('.ol-control').hide();
-        jQuery('.ol-attribution').show();
-    }
+    if (!heatmap)
+        jQuery("#loader").hide();
 
     changeZoom("init");
     changeCenter("init");
@@ -2076,9 +2085,7 @@ function startPage() {
     if (pTracks)
         setTimeout(TAR.planeMan.refresh, 10000);
 
-    window.addEventListener("beforeunload", function (event) {
-        clearIntervalTimers();
-    });
+    window.addEventListener("beforeunload", clearIntervalTimers);
 
     if (heatmap || replay || showTrace || pTracks || inhibitFetch) {
         afterFirstFetch();
@@ -5489,10 +5496,13 @@ function refresh(redraw) {
     // before planeman refresh / mapRefresh
     updateVisible();
 
+    mapRefresh(redraw);
+
     //console.time("refreshTable");
     TAR.planeMan.refresh();
     //console.timeEnd("refreshTable");
-    mapRefresh(redraw);
+
+
     refreshSelected();
     refreshHighlighted();