[core] Pass-by-const ref in GeometryTileFeature::getProperties()

1 files changed, 2 insertions, 2 deletions

diff --git a/src/mbgl/layout/symbol_feature.hpp b/src/mbgl/layout/symbol_feature.hpp
index e16dd0b2f3..0773c48d39 100644
--- a/src/mbgl/layout/symbol_feature.hpp
+++ b/src/mbgl/layout/symbol_feature.hpp
@@ -15,10 +15,10 @@ public:
         feature(std::move(feature_)),
         geometry(feature->getGeometries()) // we need a mutable copy of the geometry for mergeLines()
     {}
-    
+
     FeatureType getType() const override { return feature->getType(); }
     optional<Value> getValue(const std::string& key) const override { return feature->getValue(key); };
-    std::unordered_map<std::string,Value> getProperties() const override { return feature->getProperties(); };
+    const PropertyMap& getProperties() const override { return feature->getProperties(); };
     FeatureIdentifier getID() const override { return feature->getID(); };
     GeometryCollection getGeometries() const override { return geometry; };