- Use modern esper engine if we detect browser support it.

- Change streaming batch size depending on how far into simulation we are.
- Hoist try catch out of onWorldLoad so Chrome and JIT it.

app/assets/javascripts/workers/aether_worker.js

@@ -1,7 +1,18 @@
 var window = self;
 var Global = self;
 
-importScripts("/javascripts/lodash.js", "/javascripts/aether.js", "/javascripts/esper.js");
+importScripts("/javascripts/lodash.js", "/javascripts/aether.js");
+
+try {
+  //Detect very modern javascript support.
+  (0,eval("'use strict'; let test = (class Test { *gen() { yield yield * () => WeakMap; } });"));
+  console.log("Modern javascript detected, aw yeah!");
+  self.importScripts('/javascripts/esper.modern.js');  
+} catch (e) {
+  console.log("Legacy javascript detected, falling back...", e.message);
+  self.importScripts('/javascripts/esper.js');  
+}
+
 //console.log("Aether Tome worker has finished importing scripts.");
 var aethers = {};
 var languagesImported = {};

app/assets/javascripts/workers/worker_world.js

@@ -63,7 +63,18 @@ var console = {
 console.error = console.warn = console.info = console.debug = console.log;
 self.console = console;
 
-self.importScripts('/javascripts/lodash.js', '/javascripts/world.js', '/javascripts/aether.js', '/javascripts/esper.js');
+self.importScripts('/javascripts/lodash.js', '/javascripts/world.js', '/javascripts/aether.js');
+try {
+  //Detect very modern javascript support.
+  (0,eval("'use strict'; let test = (class Test { *gen() { yield yield * () => WeakMap; } });"));
+  console.log("Modern javascript detected, aw yeah!");
+  self.importScripts('/javascripts/esper.modern.js');  
+} catch (e) {
+  console.log("Legacy javascript detected, falling back...", e.message);
+  self.importScripts('/javascripts/esper.js');  
+}
+
+
 var myImportScripts = importScripts;
 
 var languagesImported = {};
@@ -402,6 +413,17 @@ self.serializeFramesSoFar = function serializeFramesSoFar() {
   self.world.framesSerializedSoFar = self.world.frames.length;
 };
 
+function trySerialize() {
+  try {
+    var serialized = self.world.serialize();
+  }
+  catch(error) {
+    console.log("World serialization error:", error.toString() + "\n" + error.stack || error.stackTrace);
+    return false;
+  }
+  return serialized;
+}
+
 self.onWorldLoaded = function onWorldLoaded() {
   if(self.world.framesSerializedSoFar == self.world.frames.length) return;
   if(self.world.ended)
@@ -419,12 +441,9 @@ self.onWorldLoaded = function onWorldLoaded() {
     return console.log('Headless simulation completed in ' + diff + 'ms.');
 
   var worldEnded = self.world.ended;
+  var serialized;
   var transferableSupported = self.transferableSupported();
-  try {
-    var serialized = self.world.serialize();
-  }
-  catch(error) {
-    console.log("World serialization error:", error.toString() + "\n" + error.stack || error.stackTrace);
+  if ( !( serialized = trySerialize()) ) {
     self.destroyWorld();
     return;
   }

app/lib/world/world.coffee

@@ -162,11 +162,25 @@ module.exports = class World
 
   shouldContinueLoading: (t1, loadProgressCallback, skipDeferredLoading, continueLaterFn) ->
     t2 = now()
+    chunkSize = @frames.length - @framesSerializedSoFar
+    simedTime = @frames.length / @frameRate
+
+    chunkTime = switch
+      when simedTime > 15 then 7
+      when simedTime > 10 then 5
+      when simedTime > 5 then 3
+      when simedTime > 2 then 1
+      else 0.5
+
+    bailoutTime = Math.max(2000*chunkTime, 10000)
+
+    dt = t2 - t1
+
     if @realTime
       shouldUpdateProgress = @shouldUpdateRealTimePlayback t2
       shouldDelayRealTimeSimulation = not shouldUpdateProgress and @shouldDelayRealTimeSimulation t2
     else
-      shouldUpdateProgress = t2 - t1 > PROGRESS_UPDATE_INTERVAL# and (@frames.length - @framesSerializedSoFar >= @frameRate or t2 - t1 > 1000)
+      shouldUpdateProgress = (dt > PROGRESS_UPDATE_INTERVAL and (chunkSize / @frameRate >= chunkTime) or dt > bailoutTime)
       shouldDelayRealTimeSimulation = false
     return true unless shouldUpdateProgress or shouldDelayRealTimeSimulation
     # Stop loading frames for now; continue in a moment.

config.coffee

@@ -207,6 +207,7 @@ exports.config =
       copyTo:
         'lib/ace': ['node_modules/ace-builds/src-min-noconflict/*']
         'fonts': ['bower_components/openSansCondensed/*', 'bower_components/openSans/*']
+        'javascripts': ['bower_components/esper.js/esper.modern.js']
     autoReload:
       delay: 1000