diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index d18df67a0..e5eabdac4 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -82,6 +82,7 @@ public:
         StyleInfo                 = 1 << 0,
         Debug                     = 1 << 1,
         DefaultTransitionDuration = 1 << 2,
+        Classes                   = 1 << 3,
     };
     void triggerUpdate(Update = Update::Nothing);
 
@@ -251,8 +252,6 @@ private:
 
     const std::unique_ptr<MapData> data;
 
-    std::vector<std::string> classes;
-
     std::set<util::ptr<StyleSource>> activeSources;
 
     std::atomic<UpdateType> updated;
diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index c57ed3dfb..1473346a3 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -609,43 +609,28 @@ std::chrono::steady_clock::time_point Map::getTime() const {
 }
 
 void Map::addClass(const std::string& klass) {
-    if (hasClass(klass)) return;
-    classes.push_back(klass);
-    if (style) {
-        style->cascadeClasses(classes);
-        if (style->hasTransitions()) {
-            triggerUpdate();
-        }
+    if (data->addClass(klass)) {
+        triggerUpdate(Update::Classes);
     }
 }
 
 void Map::removeClass(const std::string& klass) {
-    if (!hasClass(klass)) return;
-    classes.erase(std::remove(classes.begin(), classes.end(), klass), classes.end());
-    if (style) {
-        style->cascadeClasses(classes);
-        if (style->hasTransitions()) {
-            triggerUpdate();
-        }
+    if (data->removeClass(klass)) {
+        triggerUpdate(Update::Classes);
     }
 }
 
-void Map::setClasses(const std::vector<std::string>& classes_) {
-    classes = classes_;
-    if (style) {
-        style->cascadeClasses(classes);
-        if (style->hasTransitions()) {
-            triggerUpdate();
-        }
-    }
+void Map::setClasses(const std::vector<std::string>& classes) {
+    data->setClasses(classes);
+    triggerUpdate(Update::Classes);
 }
 
 bool Map::hasClass(const std::string& klass) const {
-    return std::find(classes.begin(), classes.end(), klass) != classes.end();
+    return data->hasClass(klass);
 }
 
 std::vector<std::string> Map::getClasses() const {
-   return classes;
+    return data->getClasses();
 }
 
 void Map::setDefaultTransitionDuration(std::chrono::steady_clock::duration duration) {
@@ -753,7 +738,7 @@ void Map::loadStyleJSON(const std::string& json, const std::string& base) {
     style = std::make_shared<Style>();
     style->base = base;
     style->loadJSON((const uint8_t *)json.c_str());
-    style->cascadeClasses(classes);
+    style->cascadeClasses(data->getClasses());
     style->setDefaultTransitionDuration(data->getDefaultTransitionDuration());
 
     const std::string glyphURL = util::mapbox::normalizeGlyphsURL(style->glyph_url, getAccessToken());
@@ -778,6 +763,11 @@ void Map::prepare() {
             style->setDefaultTransitionDuration(data->getDefaultTransitionDuration());
         }
     }
+    if (u & static_cast<UpdateType>(Update::Classes)) {
+        if (style) {
+            style->cascadeClasses(data->getClasses());
+        }
+    }
 
     // Update transform transitions.
 
diff --git a/src/mbgl/map/map_data.cpp b/src/mbgl/map/map_data.cpp
new file mode 100644
index 000000000..23bc09499
--- /dev/null
+++ b/src/mbgl/map/map_data.cpp
@@ -0,0 +1,44 @@
+#include "map_data.hpp"
+
+#include <algorithm>
+
+namespace mbgl {
+
+// Adds the class if it's not yet set. Returns true when it added the class, and false when it
+// was already present.
+bool MapData::addClass(const std::string& klass) {
+    Lock lock(mtx);
+    if (std::find(classes.begin(), classes.end(), klass) != classes.end()) return false;
+    classes.push_back(klass);
+    return true;
+}
+
+// Removes the class if it's present. Returns true when it remvoed the class, and false when it
+// was not present.
+bool MapData::removeClass(const std::string& klass) {
+    Lock lock(mtx);
+    const auto it = std::find(classes.begin(), classes.end(), klass);
+    if (it != classes.end()) {
+        classes.erase(it);
+        return true;
+    }
+    return false;
+}
+
+// Returns true when class is present in the list of currently set classes.
+bool MapData::hasClass(const std::string& klass) const {
+    Lock lock(mtx);
+    return std::find(classes.begin(), classes.end(), klass) != classes.end();
+}
+
+void MapData::setClasses(const std::vector<std::string>& klasses) {
+    Lock lock(mtx);
+    classes = klasses;
+}
+
+std::vector<std::string> MapData::getClasses() const {
+    Lock lock(mtx);
+    return classes;
+}
+
+}
\ No newline at end of file
diff --git a/src/mbgl/map/map_data.hpp b/src/mbgl/map/map_data.hpp
index 29ba22711..c0d57134d 100644
--- a/src/mbgl/map/map_data.hpp
+++ b/src/mbgl/map/map_data.hpp
@@ -5,6 +5,7 @@
 #include <mutex>
 #include <atomic>
 #include <chrono>
+#include <vector>
 
 namespace mbgl {
 
@@ -41,6 +42,24 @@ public:
         accessToken = token;
     }
 
+    // Adds the class if it's not yet set. Returns true when it added the class, and false when it
+    // was already present.
+    bool addClass(const std::string& klass);
+
+    // Removes the class if it's present. Returns true when it remvoed the class, and false when it
+    // was not present.
+    bool removeClass(const std::string& klass);
+
+    // Returns true when class is present in the list of currently set classes.
+    bool hasClass(const std::string& klass) const;
+
+    // Changes the list of currently set classes to the new list.
+    void setClasses(const std::vector<std::string>& klasses);
+
+    // Returns a list of all currently set classes.
+    std::vector<std::string> getClasses() const;
+
+
     inline bool getDebug() const {
         return debug;
     }
@@ -72,6 +91,7 @@ private:
 
     StyleInfo styleInfo;
     std::string accessToken;
+    std::vector<std::string> classes;
     std::atomic<uint8_t> debug { false };
     std::atomic<std::chrono::steady_clock::time_point::duration> animationTime;
     std::atomic<std::chrono::steady_clock::duration> defaultTransitionDuration;