1 files changed, 35 insertions, 1 deletions
diff --git a/platform/darwin/src/MGLStyleValue_Private.h b/platform/darwin/src/MGLStyleValue_Private.h
index ba4b413a3c..5124c29a90 100644
--- a/platform/darwin/src/MGLStyleValue_Private.h
+++ b/platform/darwin/src/MGLStyleValue_Private.h
@@ -10,6 +10,7 @@
 #import "MGLConversion.h"
 #include <mbgl/style/conversion/property_value.hpp>
 #include <mbgl/style/conversion/data_driven_property_value.hpp>
+#include <mbgl/style/conversion/heatmap_color_property_value.hpp>
 #include <mbgl/style/conversion/position.hpp>
 #import <mbgl/style/types.hpp>
 
@@ -52,11 +53,20 @@ public:
         return mbglValue.evaluate(evaluator);
     }
     
+    // Convert an mbgl heatmap color property value into an mgl style value
+    NSExpression *toExpression(const mbgl::style::HeatmapColorPropertyValue &mbglValue) {
+        if (mbglValue.isUndefined()) {
+            return nil;
+        }
+        return [NSExpression mgl_expressionWithJSONObject:MGLJSONObjectFromMBGLExpression(mbglValue.getExpression())];
+    }
+
     /**
      Converts an NSExpression to an mbgl property value.
      */
     template <typename MBGLValue>
-    MBGLValue toPropertyValue(NSExpression *expression) {
+    typename std::enable_if_t<!std::is_same<MBGLValue, mbgl::style::HeatmapColorPropertyValue>::value,
+    MBGLValue> toPropertyValue(NSExpression *expression) {
         if (!expression) {
             return {};
         }
@@ -85,6 +95,30 @@ public:
         
         return *value;
     }
+    
+    /**
+     Converts an NSExpression to an mbgl property value.
+     */
+    template <typename MBGLValue>
+    typename std::enable_if_t<std::is_same<MBGLValue, mbgl::style::HeatmapColorPropertyValue>::value,
+    MBGLValue> toPropertyValue(NSExpression *expression) {
+        if (!expression) {
+            return {};
+        }
+        
+        NSArray *jsonExpression = expression.mgl_jsonExpressionObject;
+        
+        mbgl::style::conversion::Error valueError;
+        auto value = mbgl::style::conversion::convert<mbgl::style::HeatmapColorPropertyValue>(
+            mbgl::style::conversion::makeConvertible(jsonExpression), valueError);
+        if (!value) {
+            [NSException raise:NSInvalidArgumentException
+                        format:@"Invalid property value: %@", @(valueError.message.c_str())];
+            return {};
+        }
+        
+        return *value;
+    }
 
 private: // Private utilities for converting from mgl to mbgl values