Schedule the runtime on the runloop of its owner thread

build/project-template/__PROJECT_NAME__/main.m

@@ -38,6 +38,8 @@ int main(int argc, char *argv[]) {
 #endif
     [TNSRuntime initializeMetadata:&startOfMetadataSection];
     runtime = [[TNSRuntime alloc] initWithApplicationPath:applicationPath];
+    [runtime scheduleInRunLoop:[NSRunLoop currentRunLoop]
+                       forMode:NSRunLoopCommonModes];
 
 #ifndef NDEBUG
     [TNSRuntimeInspector setLogsToSystemConsole:YES];

cmake/main.m

@@ -12,6 +12,8 @@ int main(int argc, char *argv[]) {
     [TNSRuntime initializeMetadata:&startOfMetadataSection];
     runtime = [[TNSRuntime alloc]
         initWithApplicationPath:[NSBundle mainBundle].bundlePath];
+    [runtime scheduleInRunLoop:[NSRunLoop currentRunLoop]
+                       forMode:NSRunLoopCommonModes];
     TNSRuntimeInspector.logsToSystemConsole = YES;
 
 #ifndef NDEBUG

examples/BlankApp/main.m

@@ -18,6 +18,8 @@ int main(int argc, char *argv[]) {
     [TNSRuntime initializeMetadata:&startOfMetadataSection];
     TNSRuntime *runtime = [[TNSRuntime alloc]
         initWithApplicationPath:[NSBundle mainBundle].bundlePath];
+    [runtime scheduleInRunLoop:[NSRunLoop currentRunLoop]
+                       forMode:NSRunLoopCommonModes];
     TNSRuntimeInspector.logsToSystemConsole = YES;
 
     NSError *error = nil;

src/NativeScript/GlobalObject.h

@@ -124,6 +124,11 @@ class GlobalObject : public JSC::JSGlobalObject {
         return this->_fastEnumerationIteratorStructure.get();
     }
 
+    void setMicrotaskRunLoopAndMode(CFRunLoopRef runLoop, CFTypeRef mode) {
+        this->_microtaskRunLoop = runLoop;
+        this->_microtaskRunLoopMode = mode;
+    }
+
 #if defined(__LP64__) && __LP64__
     JSC::WeakGCMap<const void*, ObjCWrapperObject>& taggedPointers() {
         return this->_taggedPointers;
@@ -145,6 +150,9 @@ class GlobalObject : public JSC::JSGlobalObject {
 
     WTF::String _applicationPath;
 
+    WTF::RetainPtr<CFRunLoopRef> _microtaskRunLoop;
+    WTF::RetainPtr<CFTypeRef> _microtaskRunLoopMode;
+
     JSC::WriteBarrier<JSC::Structure> _objCMethodCallStructure;
     JSC::WriteBarrier<JSC::Structure> _objCConstructorCallStructure;
     JSC::WriteBarrier<JSC::Structure> _objCBlockCallStructure;

src/NativeScript/GlobalObject.mm

@@ -374,9 +374,14 @@ static EncodedJSValue JSC_HOST_CALL collectGarbage(ExecState* execState) {
 }
 
 void GlobalObject::queueTaskToEventLoop(const JSGlobalObject* globalObject, WTF::PassRefPtr<Microtask> task) {
-    CFRunLoopPerformBlock(CFRunLoopGetCurrent(), kCFRunLoopCommonModes, ^{
+    auto global = jsCast<const GlobalObject*>(globalObject);
+    CFRunLoopRef runLoop = global->_microtaskRunLoop.get() ?: CFRunLoopGetCurrent();
+    CFTypeRef mode = global->_microtaskRunLoopMode.get() ?: kCFRunLoopCommonModes;
+
+    CFRunLoopPerformBlock(runLoop, mode, ^{
       JSLockHolder lock(globalObject->vm());
       task->run(const_cast<JSGlobalObject*>(globalObject)->globalExec());
     });
+    CFRunLoopWakeUp(runLoop);
 }
 }

src/NativeScript/TNSRuntime.h

@@ -21,6 +21,10 @@ FOUNDATION_EXTERN void TNSSetUncaughtErrorHandler(TNSUncaughtErrorHandler handle
 
 - (instancetype)initWithApplicationPath:(NSString*)applicationPath;
 
+- (void)scheduleInRunLoop:(NSRunLoop*)runLoop forMode:(NSString*)mode;
+
+- (void)removeFromRunLoop:(NSRunLoop*)runLoop forMode:(NSString*)mode;
+
 - (JSGlobalContextRef)globalContext;
 
 - (void)executeModule:(NSString*)entryPointModuleIdentifier;

src/NativeScript/TNSRuntime.mm

@@ -63,6 +63,14 @@ - (instancetype)initWithApplicationPath:(NSString*)applicationPath {
     return self;
 }
 
+- (void)scheduleInRunLoop:(NSRunLoop*)runLoop forMode:(NSString*)mode {
+    self->_globalObject->setMicrotaskRunLoopAndMode([runLoop getCFRunLoop], mode);
+}
+
+- (void)removeFromRunLoop:(NSRunLoop*)runLoop forMode:(NSString*)mode {
+    self->_globalObject->setMicrotaskRunLoopAndMode(nullptr, nullptr);
+}
+
 - (JSGlobalContextRef)globalContext {
     return toGlobalRef(self->_globalObject->globalExec());
 }

tests/TestRunner/app/Promises.js

@@ -0,0 +1,5 @@
+describe("Promise scheduling", function () {
+   it("should be executed", function(done) {
+       Promise.resolve().then(done); 
+   });
+});

tests/TestRunner/app/bootstrap.js

@@ -57,6 +57,8 @@ require('./shared');
 require('./ApiTests');
 require('./DeclarationConflicts');
 
+require('./Promises');
+
 execute();
 
 UIApplicationMain(0, null, null, null);