Merge pull request #959 from NativeScript/pete/fix-console

fix(console): implement a smarter JSON.stringify which doesn't crash on Circular references

Author: petekanev

test-app/runtime/src/main/cpp/V8GlobalHelpers.cpp

@@ -9,6 +9,8 @@
 using namespace v8;
 using namespace std;
 
+static std::map<v8::Isolate*, v8::Persistent<v8::Function>*> isolateToPersistentSmartJSONStringify = std::map<v8::Isolate*, v8::Persistent<v8::Function>*>();
+
 string tns::ConvertToString(const Local<v8::String>& s) {
     if (s.IsEmpty()) {
         return string();
@@ -18,16 +20,87 @@ string tns::ConvertToString(const Local<v8::String>& s) {
     }
 }
 
+Local<Function> GetSmartJSONStringifyFunction(Isolate* isolate) {
+    auto it = isolateToPersistentSmartJSONStringify.find(isolate);
+    if (it != isolateToPersistentSmartJSONStringify.end()) {
+        auto smartStringifyPersistentFunction = it->second;
+
+        return smartStringifyPersistentFunction->Get(isolate);
+    }
+
+    string smartStringifyFunctionScript =
+        "(function () {\n"
+        "    function smartStringify(object) {\n"
+        "        seen = [];\n"
+        "        var replacer = function (key, value) {\n"
+        "            if (value != null && typeof value == \"object\") {\n"
+        "                if (seen.indexOf(value) >= 0) {\n"
+        "                    if (key) {\n"
+        "                        return \"[Circular]\";\n"
+        "                    }\n"
+        "                    return;\n"
+        "                }\n"
+        "                seen.push(value);\n"
+        "            }\n"
+        "            return value;\n"
+        "        };\n"
+        "        return JSON.stringify(object, replacer, 2);\n"
+        "    }\n"
+        "    return smartStringify;\n"
+        "})();";
+
+    auto source = tns::ArgConverter::ConvertToV8String(isolate, smartStringifyFunctionScript);
+    auto context = isolate->GetCurrentContext();
+
+    Local<Script> script;
+    auto maybeScript = Script::Compile(context, source).ToLocal(&script);
+
+    if (script.IsEmpty()) {
+        return Local<Function>();
+    }
+
+    Local<Value> result;
+    auto maybeResult = script->Run(context).ToLocal(&result);
+
+    if (result.IsEmpty() && !result->IsFunction()) {
+        return Local<Function>();
+    }
+
+    auto smartStringifyFunction = result.As<Function>();
+
+    auto smartStringifyPersistentFunction = new Persistent<Function>(isolate, smartStringifyFunction);
+
+    isolateToPersistentSmartJSONStringify.insert(std::make_pair(isolate, smartStringifyPersistentFunction));
+
+    return smartStringifyPersistentFunction->Get(isolate);
+}
+
 Local<String> tns::JsonStringifyObject(Isolate* isolate, Handle<v8::Value> value) {
     v8::HandleScope scope(isolate);
 
     if (value.IsEmpty()) {
         return String::Empty(isolate);
     }
 
+    Local<Function> smartJSONStringifyFunction = GetSmartJSONStringifyFunction(isolate);
+
+    if (!smartJSONStringifyFunction.IsEmpty()) {
+        if (value->IsObject()) {
+            v8::Local<v8::Value> resultValue;
+            v8::TryCatch tc;
+
+            Local<Value> args[] = { value->ToObject() };
+            auto success = smartJSONStringifyFunction->Call(isolate->GetCurrentContext(), Undefined(isolate), 1, args).ToLocal(&resultValue);
+
+            if (success && !tc.HasCaught()) {
+                return resultValue->ToString();
+            }
+        }
+    }
+
     v8::Local<v8::String> resultString;
     v8::TryCatch tc;
-    auto success = v8::JSON::Stringify(isolate->GetCurrentContext(), value->ToObject(isolate)).ToLocal(&resultString);
+    auto success = v8::JSON::Stringify(isolate->GetCurrentContext(), value->ToObject(isolate), ArgConverter::ConvertToV8String(isolate, "2")).ToLocal(&resultString);
 
     if (!success && tc.HasCaught()) {
         auto message = tc.Message()->Get();
@@ -123,4 +196,3 @@ bool tns::V8SetPrivateValue(Isolate* isolate, const Local<Object>& obj, const Lo
 
     return res.FromMaybe(false);
 }
-

test-app/runtime/src/main/cpp/V8GlobalHelpers.h

@@ -5,6 +5,7 @@
 #include "v8.h"
 #include "include/v8.h"
 #include <string>
+#include <map>
 
 namespace tns {
 std::string ConvertToString(const v8::Local<v8::String>& s);