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NathanWalkerNathanWalker
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feat: support for meta.hot.on, meta.hot.send and custom event listeners
1 parent 7dff8ee commit 86a42f0

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‎NativeScript/runtime/HMRSupport.h‎

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Original file line numberDiff line numberDiff line change
@@ -11,6 +11,7 @@ template <class T> class Local;
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class Object;
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class Function;
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class Context;
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class Value;
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}
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namespace tns {
@@ -67,4 +68,21 @@ std::string CanonicalizeHttpUrlKey(const std::string& url);
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// - status: HTTP status code
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bool HttpFetchText(const std::string& url, std::string& out, std::string& contentType, int& status);
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// ─────────────────────────────────────────────────────────────
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// Custom HMR event support
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// Register a custom event listener (called by import.meta.hot.on())
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void RegisterHotEventListener(v8::Isolate* isolate, const std::string& event, v8::Local<v8::Function> cb);
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// Get all listeners for a custom event
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std::vector<v8::Local<v8::Function>> GetHotEventListeners(v8::Isolate* isolate, const std::string& event);
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// Dispatch a custom event to all registered listeners
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// This should be called when the HMR WebSocket receives framework-specific events
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void DispatchHotEvent(v8::Isolate* isolate, v8::Local<v8::Context> context, const std::string& event, v8::Local<v8::Value> data);
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// Initialize the global event dispatcher function (__NS_DISPATCH_HOT_EVENT__)
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// This exposes a JavaScript-callable function that the HMR client can use to dispatch events
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void InitializeHotEventDispatcher(v8::Isolate* isolate, v8::Local<v8::Context> context);
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} // namespace tns

‎NativeScript/runtime/HMRSupport.mm‎

Lines changed: 105 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -29,6 +29,10 @@ static inline bool EndsWith(const std::string& s, const char* suffix) {
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static std::unordered_map<std::string, std::vector<v8::Global<v8::Function>>> g_hotAccept;
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static std::unordered_map<std::string, std::vector<v8::Global<v8::Function>>> g_hotDispose;
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// Custom event listeners
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// Keyed by event name (global, not per-module)
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static std::unordered_map<std::string, std::vector<v8::Global<v8::Function>>> g_hotEventListeners;
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v8::Local<v8::Object> GetOrCreateHotData(v8::Isolate* isolate, const std::string& key) {
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auto it = g_hotData.find(key);
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if (it != g_hotData.end()) {
@@ -73,6 +77,76 @@ void RegisterHotDispose(v8::Isolate* isolate, const std::string& key, v8::Local<
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return out;
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}
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void RegisterHotEventListener(v8::Isolate* isolate, const std::string& event, v8::Local<v8::Function> cb) {
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if (cb.IsEmpty()) return;
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g_hotEventListeners[event].emplace_back(v8::Global<v8::Function>(isolate, cb));
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}
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std::vector<v8::Local<v8::Function>> GetHotEventListeners(v8::Isolate* isolate, const std::string& event) {
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std::vector<v8::Local<v8::Function>> out;
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auto it = g_hotEventListeners.find(event);
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if (it != g_hotEventListeners.end()) {
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for (auto& gfn : it->second) {
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if (!gfn.IsEmpty()) out.push_back(gfn.Get(isolate));
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}
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}
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return out;
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}
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void DispatchHotEvent(v8::Isolate* isolate, v8::Local<v8::Context> context, const std::string& event, v8::Local<v8::Value> data) {
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auto callbacks = GetHotEventListeners(isolate, event);
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for (auto& cb : callbacks) {
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v8::TryCatch tryCatch(isolate);
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v8::Local<v8::Value> args[] = { data };
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v8::MaybeLocal<v8::Value> result = cb->Call(context, v8::Undefined(isolate), 1, args);
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(void)result; // Suppress unused result warning
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if (tryCatch.HasCaught()) {
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// Log error but continue to other listeners
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if (tns::IsScriptLoadingLogEnabled()) {
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Log(@"[import.meta.hot] Error in event listener for '%s'", event.c_str());
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}
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}
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}
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}
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void InitializeHotEventDispatcher(v8::Isolate* isolate, v8::Local<v8::Context> context) {
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using v8::FunctionCallbackInfo;
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using v8::Local;
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using v8::Value;
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// Create a global function __NS_DISPATCH_HOT_EVENT__(event, data)
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// that the HMR client can call to dispatch events to registered listeners
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auto dispatchCb = [](const FunctionCallbackInfo<Value>& info) {
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v8::Isolate* iso = info.GetIsolate();
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v8::Local<v8::Context> ctx = iso->GetCurrentContext();
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if (info.Length() < 1 || !info[0]->IsString()) {
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info.GetReturnValue().Set(v8::Boolean::New(iso, false));
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return;
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}
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v8::String::Utf8Value eventName(iso, info[0]);
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std::string event = *eventName ? *eventName : "";
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if (event.empty()) {
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info.GetReturnValue().Set(v8::Boolean::New(iso, false));
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return;
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}
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v8::Local<Value> data = info.Length() > 1 ? info[1] : v8::Undefined(iso).As<Value>();
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if (tns::IsScriptLoadingLogEnabled()) {
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Log(@"[import.meta.hot] Dispatching event '%s'", event.c_str());
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}
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DispatchHotEvent(iso, ctx, event, data);
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info.GetReturnValue().Set(v8::Boolean::New(iso, true));
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};
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v8::Local<v8::Object> global = context->Global();
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v8::Local<v8::Function> dispatchFn = v8::Function::New(context, dispatchCb).ToLocalChecked();
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global->CreateDataProperty(context, tns::ToV8String(isolate, "__NS_DISPATCH_HOT_EVENT__"), dispatchFn).Check();
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}
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void InitializeImportMetaHot(v8::Isolate* isolate,
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v8::Local<v8::Context> context,
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v8::Local<v8::Object> importMeta,
@@ -194,6 +268,31 @@ void InitializeImportMetaHot(v8::Isolate* isolate,
194268
info.GetReturnValue().Set(v8::Undefined(info.GetIsolate()));
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};
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271+
// on(event, cb) — register custom event listener
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auto onCb = [](const FunctionCallbackInfo<Value>& info) {
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v8::Isolate* iso = info.GetIsolate();
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if (info.Length() < 2) {
275+
info.GetReturnValue().Set(v8::Undefined(iso));
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return;
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}
278+
if (!info[0]->IsString() || !info[1]->IsFunction()) {
279+
info.GetReturnValue().Set(v8::Undefined(iso));
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return;
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}
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v8::String::Utf8Value eventName(iso, info[0]);
283+
std::string event = *eventName ? *eventName : "";
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if (!event.empty()) {
285+
RegisterHotEventListener(iso, event, info[1].As<v8::Function>());
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}
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info.GetReturnValue().Set(v8::Undefined(iso));
288+
};
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290+
// send(event, data) — send event to server (no-op on client, could be wired to WebSocket)
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auto sendCb = [](const FunctionCallbackInfo<Value>& info) {
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// No-op for now - could be wired to WebSocket for client->server events
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info.GetReturnValue().Set(v8::Undefined(info.GetIsolate()));
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};
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197296
Local<Object> hot = Object::New(isolate);
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// Stable flags
199298
hot->CreateDataProperty(context, tns::ToV8String(isolate, "data"),
@@ -213,6 +312,12 @@ void InitializeImportMetaHot(v8::Isolate* isolate,
213312
hot->CreateDataProperty(
214313
context, tns::ToV8String(isolate, "invalidate"),
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v8::Function::New(context, invalidateCb, makeKeyData(key)).ToLocalChecked()).Check();
315+
hot->CreateDataProperty(
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context, tns::ToV8String(isolate, "on"),
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v8::Function::New(context, onCb, makeKeyData(key)).ToLocalChecked()).Check();
318+
hot->CreateDataProperty(
319+
context, tns::ToV8String(isolate, "send"),
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v8::Function::New(context, sendCb, makeKeyData(key)).ToLocalChecked()).Check();
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217322
// Attach to import.meta
218323
importMeta->CreateDataProperty(

‎NativeScript/runtime/Runtime.mm‎

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -339,6 +339,16 @@ void DisposeIsolateWhenPossible(Isolate* isolate) {
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PromiseProxy::Init(context);
340340
Console::Init(context);
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WeakRef::Init(context);
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343+
// Initialize HMR event dispatcher for dev mode
344+
// This provides __NS_DISPATCH_HOT_EVENT__ global for the HMR client
345+
if (RuntimeConfig.IsDebug) {
346+
try {
347+
tns::InitializeHotEventDispatcher(isolate, context);
348+
} catch (...) {
349+
// Don't crash if HMR setup fails
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}
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}
342352

343353
// Implement Blob per the File API spec (https://w3c.github.io/FileAPI/#blob-section)
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// This provides a complete Blob implementation with:

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