2 files changed, 19 insertions, 11 deletions
diff --git a/src/corelib/kernel/qeventdispatcher_wasm.cpp b/src/corelib/kernel/qeventdispatcher_wasm.cpp
index 5f4c46c07f..f5061f35d7 100644
--- a/src/corelib/kernel/qeventdispatcher_wasm.cpp
+++ b/src/corelib/kernel/qeventdispatcher_wasm.cpp
@@ -218,9 +218,12 @@ QEventDispatcherWasm::QEventDispatcherWasm()
 #if QT_CONFIG(thread)
         g_mainThread = pthread_self();
 #endif
+
         // Call the "onLoaded" JavaScript callback, unless startup tasks
-        // have been registered which should complete first.
-        checkCallQtLoaded();
+        // have been registered which should complete first. Run async
+        // to make sure event dispatcher construction (in particular any
+        // subclass construction) has completed first.
+        runAsync(callOnLoadedIfRequired);
     } else {
 #if QT_CONFIG(thread)
         std::lock_guard<std::mutex> lock(g_staticDataMutex);
@@ -916,10 +919,10 @@ void QEventDispatcherWasm::registerStartupTask()
 void QEventDispatcherWasm::completeStarupTask()
 {
     --g_startupTasks;
-    checkCallQtLoaded();
+    callOnLoadedIfRequired();
 }
 
-void QEventDispatcherWasm::checkCallQtLoaded()
+void QEventDispatcherWasm::callOnLoadedIfRequired()
 {
     if (g_startupTasks > 0)
         return;
@@ -929,12 +932,16 @@ void QEventDispatcherWasm::checkCallQtLoaded()
         return;
     qtLoadedCalled = true;
 
-    QTimer::singleShot(0, [](){
-        emscripten::val qt = emscripten::val::module_property("qt");
-        if (qt.isUndefined())
-            return;
-        qt.call<void>("onLoaded");
-    });
+    Q_ASSERT(g_mainThreadEventDispatcher);
+    g_mainThreadEventDispatcher->onLoaded();
+}
+
+void QEventDispatcherWasm::onLoaded()
+{
+    emscripten::val qt = emscripten::val::module_property("qt");
+    if (qt.isUndefined())
+        return;
+    qt.call<void>("onLoaded");
 }
 
 namespace {
diff --git a/src/corelib/kernel/qeventdispatcher_wasm_p.h b/src/corelib/kernel/qeventdispatcher_wasm_p.h
index afffc8a813..0d94c48a25 100644
--- a/src/corelib/kernel/qeventdispatcher_wasm_p.h
+++ b/src/corelib/kernel/qeventdispatcher_wasm_p.h
@@ -59,7 +59,8 @@ public:
 
     static void registerStartupTask();
     static void completeStarupTask();
-    static void checkCallQtLoaded();
+    static void callOnLoadedIfRequired();
+    virtual void onLoaded();
 
 protected:
     virtual bool processPostedEvents();