Allow checking for and catching errors from QJSEngine

As you can manually throw an error, you should be able to catch it
again, too.

Change-Id: I82475df1969a1fd76f4cf5fc0a8d921dfafaef89
Reviewed-by: Maximilian Goldstein <max.goldstein@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

2 files changed, 29 insertions, 0 deletions

diff --git a/src/qml/jsapi/qjsengine.cpp b/src/qml/jsapi/qjsengine.cpp
index 96fcd99de4..a0e2cb2c3a 100644
--- a/src/qml/jsapi/qjsengine.cpp
+++ b/src/qml/jsapi/qjsengine.cpp
@@ -927,6 +927,33 @@ void QJSEngine::throwError(QJSValue::ErrorType errorType, const QString &message
 }
 
 /*!
+ * Returns \c true if the last JavaScript execution resulted in an exception or
+ * if throwError() was called. Otherwise returns \c false. Mind that evaluate()
+ * catches any exceptions thrown in the evaluated code.
+ *
+ * \since Qt 6.1
+ */
+bool QJSEngine::hasError() const
+{
+    return m_v4Engine->hasException;
+}
+
+/*!
+ * If an exception is currently pending, catches it and returns it as a
+ * QJSValue. Otherwise returns undefined as QJSValue. After calling this method
+ * hasError() returns \c false.
+ *
+ * \since Qt 6.1
+ */
+QJSValue QJSEngine::catchError()
+{
+    if (m_v4Engine->hasException)
+        return QJSValuePrivate::fromReturnedValue(m_v4Engine->catchException());
+    else
+        return QJSValue();
+}
+
+/*!
   \property QJSEngine::uiLanguage
   \brief the language to be used for translating user interface strings
   \since 5.15
diff --git a/src/qml/jsapi/qjsengine.h b/src/qml/jsapi/qjsengine.h
index 775f9e658a..c480a77599 100644
--- a/src/qml/jsapi/qjsengine.h
+++ b/src/qml/jsapi/qjsengine.h
@@ -121,6 +121,8 @@ public:
 
     void throwError(const QString &message);
     void throwError(QJSValue::ErrorType errorType, const QString &message = QString());
+    bool hasError() const;
+    QJSValue catchError();
 
     QString uiLanguage() const;
     void setUiLanguage(const QString &language);