diff --git a/src/controllers/scripting/controllerscriptenginebase.cpp b/src/controllers/scripting/controllerscriptenginebase.cpp
index 74c4eaa4041..14c6fde111b 100644
--- a/src/controllers/scripting/controllerscriptenginebase.cpp
+++ b/src/controllers/scripting/controllerscriptenginebase.cpp
@@ -74,7 +74,7 @@ void ControllerScriptEngineBase::reload() {
 }
 
 bool ControllerScriptEngineBase::executeFunction(
-        QJSValue functionObject, QJSValueList args) {
+        QJSValue functionObject, const QJSValueList& args) {
     // This function is called from outside the controller engine, so we can't
     // use VERIFY_OR_DEBUG_ASSERT here
     if (!m_pJSEngine) {
@@ -104,7 +104,7 @@ bool ControllerScriptEngineBase::executeFunction(
 }
 
 void ControllerScriptEngineBase::showScriptExceptionDialog(
-        QJSValue evaluationResult, bool bFatalError) {
+        const QJSValue& evaluationResult, bool bFatalError) {
     VERIFY_OR_DEBUG_ASSERT(evaluationResult.isError()) {
         return;
     }
diff --git a/src/controllers/scripting/controllerscriptenginebase.h b/src/controllers/scripting/controllerscriptenginebase.h
index 87ae4fa4019..49295dbe76b 100644
--- a/src/controllers/scripting/controllerscriptenginebase.h
+++ b/src/controllers/scripting/controllerscriptenginebase.h
@@ -23,11 +23,11 @@ class ControllerScriptEngineBase : public QObject {
 
     virtual bool initialize();
 
-    bool executeFunction(QJSValue functionObject, QJSValueList arguments);
+    bool executeFunction(QJSValue functionObject, const QJSValueList& arguments);
 
     /// Shows a UI dialog notifying of a script evaluation error.
     /// Precondition: QJSValue.isError() == true
-    void showScriptExceptionDialog(QJSValue evaluationResult, bool bFatal = false);
+    void showScriptExceptionDialog(const QJSValue& evaluationResult, bool bFatal = false);
     void throwJSError(const QString& message);
 
     inline void setTesting(bool testing) {
diff --git a/src/controllers/scripting/controllerscriptmoduleengine.h b/src/controllers/scripting/controllerscriptmoduleengine.h
index 3b6c7009810..76b14ee774c 100644
--- a/src/controllers/scripting/controllerscriptmoduleengine.h
+++ b/src/controllers/scripting/controllerscriptmoduleengine.h
@@ -11,7 +11,7 @@ class ControllerScriptModuleEngine : public ControllerScriptEngineBase {
 
     bool initialize() override;
 
-    void setModuleFileInfo(QFileInfo moduleFileInfo) {
+    void setModuleFileInfo(const QFileInfo& moduleFileInfo) {
         m_moduleFileInfo = moduleFileInfo;
     }
 
diff --git a/src/controllers/scripting/legacy/controllerscriptenginelegacy.cpp b/src/controllers/scripting/legacy/controllerscriptenginelegacy.cpp
index f0789145823..32d818c9277 100644
--- a/src/controllers/scripting/legacy/controllerscriptenginelegacy.cpp
+++ b/src/controllers/scripting/legacy/controllerscriptenginelegacy.cpp
@@ -20,9 +20,10 @@ ControllerScriptEngineLegacy::~ControllerScriptEngineLegacy() {
     shutdown();
 }
 
-bool ControllerScriptEngineLegacy::callFunctionOnObjects(QList<QString> scriptFunctionPrefixes,
+bool ControllerScriptEngineLegacy::callFunctionOnObjects(
+        const QList<QString>& scriptFunctionPrefixes,
         const QString& function,
-        QJSValueList args,
+        const QJSValueList& args,
         bool bFatalError) {
     VERIFY_OR_DEBUG_ASSERT(m_pJSEngine) {
         return false;
@@ -98,7 +99,7 @@ bool ControllerScriptEngineLegacy::initialize() {
     engineGlobalObject.setProperty(
             "engine", m_pJSEngine->newQObject(legacyScriptInterface));
 
-    for (const ControllerPreset::ScriptFileInfo& script : m_scriptFiles) {
+    for (const ControllerPreset::ScriptFileInfo& script : std::as_const(m_scriptFiles)) {
         if (!evaluateScriptFile(script.file)) {
             shutdown();
             return false;
@@ -158,7 +159,7 @@ bool ControllerScriptEngineLegacy::handleIncomingData(const QByteArray& data) {
     args << m_pJSEngine->toScriptValue(data);
     args << QJSValue(data.size());
 
-    for (const QJSValue& function : m_incomingDataFunctions) {
+    for (const QJSValue& function : std::as_const(m_incomingDataFunctions)) {
         ControllerScriptEngineBase::executeFunction(function, args);
     }
 
diff --git a/src/controllers/scripting/legacy/controllerscriptenginelegacy.h b/src/controllers/scripting/legacy/controllerscriptenginelegacy.h
index 98075376e42..d8b83bb2cda 100644
--- a/src/controllers/scripting/legacy/controllerscriptenginelegacy.h
+++ b/src/controllers/scripting/legacy/controllerscriptenginelegacy.h
@@ -35,9 +35,9 @@ class ControllerScriptEngineLegacy : public ControllerScriptEngineBase {
     bool evaluateScriptFile(const QFileInfo& scriptFile);
     void shutdown() override;
 
-    bool callFunctionOnObjects(QList<QString>,
+    bool callFunctionOnObjects(const QList<QString>& scriptFunctionPrefixes,
             const QString&,
-            QJSValueList args = QJSValueList(),
+            const QJSValueList& args = QJSValueList(),
             bool bFatalError = false);
 
     QList<QString> m_scriptFunctionPrefixes;
diff --git a/src/controllers/scripting/legacy/controllerscriptinterfacelegacy.cpp b/src/controllers/scripting/legacy/controllerscriptinterfacelegacy.cpp
index c45231f3d45..11718bf0801 100644
--- a/src/controllers/scripting/legacy/controllerscriptinterfacelegacy.cpp
+++ b/src/controllers/scripting/legacy/controllerscriptinterfacelegacy.cpp
@@ -99,7 +99,7 @@ ControlObjectScript* ControllerScriptInterfaceLegacy::getControlObjectScript(
     return coScript;
 }
 
-double ControllerScriptInterfaceLegacy::getValue(QString group, QString name) {
+double ControllerScriptInterfaceLegacy::getValue(const QString& group, const QString& name) {
     ControlObjectScript* coScript = getControlObjectScript(group, name);
     if (coScript == nullptr) {
         qWarning() << "Unknown control" << group << name
@@ -110,7 +110,7 @@ double ControllerScriptInterfaceLegacy::getValue(QString group, QString name) {
 }
 
 void ControllerScriptInterfaceLegacy::setValue(
-        QString group, QString name, double newValue) {
+        const QString& group, const QString& name, double newValue) {
     if (isnan(newValue)) {
         qWarning() << "script setting [" << group << ","
                    << name << "] to NotANumber, ignoring.";
@@ -130,7 +130,7 @@ void ControllerScriptInterfaceLegacy::setValue(
     }
 }
 
-double ControllerScriptInterfaceLegacy::getParameter(QString group, QString name) {
+double ControllerScriptInterfaceLegacy::getParameter(const QString& group, const QString& name) {
     ControlObjectScript* coScript = getControlObjectScript(group, name);
     if (coScript == nullptr) {
         qWarning() << "Unknown control" << group << name
@@ -141,7 +141,7 @@ double ControllerScriptInterfaceLegacy::getParameter(QString group, QString name
 }
 
 void ControllerScriptInterfaceLegacy::setParameter(
-        QString group, QString name, double newParameter) {
+        const QString& group, const QString& name, double newParameter) {
     if (isnan(newParameter)) {
         qWarning() << "script setting [" << group << ","
                    << name << "] to NotANumber, ignoring.";
@@ -160,7 +160,7 @@ void ControllerScriptInterfaceLegacy::setParameter(
 }
 
 double ControllerScriptInterfaceLegacy::getParameterForValue(
-        QString group, QString name, double value) {
+        const QString& group, const QString& name, double value) {
     if (isnan(value)) {
         qWarning() << "script setting [" << group << ","
                    << name << "] to NotANumber, ignoring.";
@@ -178,14 +178,14 @@ double ControllerScriptInterfaceLegacy::getParameterForValue(
     return coScript->getParameterForValue(value);
 }
 
-void ControllerScriptInterfaceLegacy::reset(QString group, QString name) {
+void ControllerScriptInterfaceLegacy::reset(const QString& group, const QString& name) {
     ControlObjectScript* coScript = getControlObjectScript(group, name);
     if (coScript != nullptr) {
         coScript->reset();
     }
 }
 
-double ControllerScriptInterfaceLegacy::getDefaultValue(QString group, QString name) {
+double ControllerScriptInterfaceLegacy::getDefaultValue(const QString& group, const QString& name) {
     ControlObjectScript* coScript = getControlObjectScript(group, name);
 
     if (coScript == nullptr) {
@@ -198,7 +198,7 @@ double ControllerScriptInterfaceLegacy::getDefaultValue(QString group, QString n
 }
 
 double ControllerScriptInterfaceLegacy::getDefaultParameter(
-        QString group, QString name) {
+        const QString& group, const QString& name) {
     ControlObjectScript* coScript = getControlObjectScript(group, name);
 
     if (coScript == nullptr) {
@@ -211,7 +211,7 @@ double ControllerScriptInterfaceLegacy::getDefaultParameter(
 }
 
 QJSValue ControllerScriptInterfaceLegacy::makeConnection(
-        QString group, QString name, const QJSValue callback) {
+        const QString& group, const QString& name, const QJSValue& callback) {
     auto pJsEngine = m_pScriptEngineLegacy->jsEngine();
     VERIFY_OR_DEBUG_ASSERT(pJsEngine) {
         return QJSValue();
@@ -254,7 +254,7 @@ QJSValue ControllerScriptInterfaceLegacy::makeConnection(
 }
 
 bool ControllerScriptInterfaceLegacy::removeScriptConnection(
-        const ScriptConnection connection) {
+        const ScriptConnection& connection) {
     ControlObjectScript* coScript =
             getControlObjectScript(connection.key.group, connection.key.item);
 
@@ -266,7 +266,7 @@ bool ControllerScriptInterfaceLegacy::removeScriptConnection(
 }
 
 void ControllerScriptInterfaceLegacy::triggerScriptConnection(
-        const ScriptConnection connection) {
+        const ScriptConnection& connection) {
     VERIFY_OR_DEBUG_ASSERT(m_pScriptEngineLegacy->jsEngine()) {
         return;
     }
@@ -288,8 +288,10 @@ void ControllerScriptInterfaceLegacy::triggerScriptConnection(
 // it is disconnected.
 // WARNING: These behaviors are quirky and confusing, so if you change this function,
 // be sure to run the ControllerScriptInterfaceTest suite to make sure you do not break old scripts.
-QJSValue ControllerScriptInterfaceLegacy::connectControl(
-        QString group, QString name, QJSValue passedCallback, bool disconnect) {
+QJSValue ControllerScriptInterfaceLegacy::connectControl(const QString& group,
+        const QString& name,
+        const QJSValue& passedCallback,
+        bool disconnect) {
     // The passedCallback may or may not actually be a function, so when
     // the actual callback function is found, store it in this variable.
     QJSValue actualCallbackFunction;
@@ -404,14 +406,14 @@ QJSValue ControllerScriptInterfaceLegacy::connectControl(
     return makeConnection(group, name, actualCallbackFunction);
 }
 
-void ControllerScriptInterfaceLegacy::trigger(QString group, QString name) {
+void ControllerScriptInterfaceLegacy::trigger(const QString& group, const QString& name) {
     ControlObjectScript* coScript = getControlObjectScript(group, name);
     if (coScript != nullptr) {
         coScript->emitValueChanged();
     }
 }
 
-void ControllerScriptInterfaceLegacy::log(QString message) {
+void ControllerScriptInterfaceLegacy::log(const QString& message) {
     controllerDebug(message);
 }
 int ControllerScriptInterfaceLegacy::beginTimer(
@@ -494,7 +496,7 @@ void ControllerScriptInterfaceLegacy::timerEvent(QTimerEvent* event) {
 }
 
 void ControllerScriptInterfaceLegacy::softTakeover(
-        QString group, QString name, bool set) {
+        const QString& group, const QString& name, bool set) {
     ControlObject* pControl = ControlObject::getControl(
             ConfigKey(group, name), ControllerDebug::shouldAssertForInvalidControlObjects());
     if (!pControl) {
@@ -508,7 +510,7 @@ void ControllerScriptInterfaceLegacy::softTakeover(
 }
 
 void ControllerScriptInterfaceLegacy::softTakeoverIgnoreNextValue(
-        QString group, const QString name) {
+        const QString& group, const QString& name) {
     ControlObject* pControl = ControlObject::getControl(
             ConfigKey(group, name), ControllerDebug::shouldAssertForInvalidControlObjects());
     if (!pControl) {
@@ -553,7 +555,7 @@ void ControllerScriptInterfaceLegacy::scratchEnable(int deck,
         double beta,
         bool ramp) {
     // If we're already scratching this deck, override that with this request
-    if (m_dx[deck]) {
+    if (static_cast<bool>(m_dx[deck])) {
         //qDebug() << "Already scratching deck" << deck << ". Overriding.";
         int timerId = m_scratchTimers.key(deck);
         killTimer(timerId);
@@ -603,7 +605,7 @@ void ControllerScriptInterfaceLegacy::scratchEnable(int deck,
     }
 
     // Initialize scratch filter
-    if (alpha && beta) {
+    if (static_cast<bool>(alpha) && static_cast<bool>(beta)) {
         m_scratchFilters[deck]->init(kAlphaBetaDt, initVelocity, alpha, beta);
     } else {
         // Use filter's defaults if not specified
diff --git a/src/controllers/scripting/legacy/controllerscriptinterfacelegacy.h b/src/controllers/scripting/legacy/controllerscriptinterfacelegacy.h
index 2043b6beadc..11087394eb5 100644
--- a/src/controllers/scripting/legacy/controllerscriptinterfacelegacy.h
+++ b/src/controllers/scripting/legacy/controllerscriptinterfacelegacy.h
@@ -20,23 +20,25 @@ class ControllerScriptInterfaceLegacy : public QObject {
 
     virtual ~ControllerScriptInterfaceLegacy();
 
-    Q_INVOKABLE double getValue(QString group, QString name);
-    Q_INVOKABLE void setValue(QString group, QString name, double newValue);
-    Q_INVOKABLE double getParameter(QString group, QString name);
-    Q_INVOKABLE void setParameter(QString group, QString name, double newValue);
-    Q_INVOKABLE double getParameterForValue(QString group, QString name, double value);
-    Q_INVOKABLE void reset(QString group, QString name);
-    Q_INVOKABLE double getDefaultValue(QString group, QString name);
-    Q_INVOKABLE double getDefaultParameter(QString group, QString name);
-    Q_INVOKABLE QJSValue makeConnection(QString group, QString name, const QJSValue callback);
+    Q_INVOKABLE double getValue(const QString& group, const QString& name);
+    Q_INVOKABLE void setValue(const QString& group, const QString& name, double newValue);
+    Q_INVOKABLE double getParameter(const QString& group, const QString& name);
+    Q_INVOKABLE void setParameter(const QString& group, const QString& name, double newValue);
+    Q_INVOKABLE double getParameterForValue(
+            const QString& group, const QString& name, double value);
+    Q_INVOKABLE void reset(const QString& group, const QString& name);
+    Q_INVOKABLE double getDefaultValue(const QString& group, const QString& name);
+    Q_INVOKABLE double getDefaultParameter(const QString& group, const QString& name);
+    Q_INVOKABLE QJSValue makeConnection(
+            const QString& group, const QString& name, const QJSValue& callback);
     // DEPRECATED: Use makeConnection instead.
-    Q_INVOKABLE QJSValue connectControl(QString group,
-            QString name,
-            const QJSValue passedCallback,
+    Q_INVOKABLE QJSValue connectControl(const QString& group,
+            const QString& name,
+            const QJSValue& passedCallback,
             bool disconnect = false);
     // Called indirectly by the objects returned by connectControl
-    Q_INVOKABLE void trigger(QString group, QString name);
-    Q_INVOKABLE void log(QString message);
+    Q_INVOKABLE void trigger(const QString& group, const QString& name);
+    Q_INVOKABLE void log(const QString& message);
     Q_INVOKABLE int beginTimer(int interval, QJSValue scriptCode, bool oneShot = false);
     Q_INVOKABLE void stopTimer(int timerId);
     Q_INVOKABLE void scratchEnable(int deck,
@@ -48,15 +50,15 @@ class ControllerScriptInterfaceLegacy : public QObject {
     Q_INVOKABLE void scratchTick(int deck, int interval);
     Q_INVOKABLE void scratchDisable(int deck, bool ramp = true);
     Q_INVOKABLE bool isScratching(int deck);
-    Q_INVOKABLE void softTakeover(QString group, QString name, bool set);
-    Q_INVOKABLE void softTakeoverIgnoreNextValue(QString group, QString name);
+    Q_INVOKABLE void softTakeover(const QString& group, const QString& name, bool set);
+    Q_INVOKABLE void softTakeoverIgnoreNextValue(const QString& group, const QString& name);
     Q_INVOKABLE void brake(int deck, bool activate, double factor = 1.0, double rate = 1.0);
     Q_INVOKABLE void spinback(int deck, bool activate, double factor = 1.8, double rate = -10.0);
     Q_INVOKABLE void softStart(int deck, bool activate, double factor = 1.0);
 
-    bool removeScriptConnection(const ScriptConnection conn);
+    bool removeScriptConnection(const ScriptConnection& conn);
     /// Execute a ScriptConnection's JS callback
-    void triggerScriptConnection(const ScriptConnection conn);
+    void triggerScriptConnection(const ScriptConnection& conn);
 
     /// Handler for timers that scripts set.
     virtual void timerEvent(QTimerEvent* event);