diff --git a/src/hnsw/hnsw_const.rs b/src/hnsw/hnsw_const.rs
index 2a76e21..aae9b41 100644
--- a/src/hnsw/hnsw_const.rs
+++ b/src/hnsw/hnsw_const.rs
@@ -64,6 +64,21 @@ where
             params,
         }
     }
+
+    pub fn transform_features<T2, F>(self, f: F) -> Hnsw<Met, T2, R, M, M0>
+    where
+        F: Fn(T) -> T2,
+    {
+        let features = self.features.into_iter().map(f).collect();
+        Hnsw {
+            metric: self.metric,
+            zero: self.zero,
+            features,
+            layers: self.layers,
+            prng: self.prng,
+            params: self.params,
+        }
+    }
 }
 
 impl<Met, T, R, const M: usize, const M0: usize> Knn for Hnsw<Met, T, R, M, M0>
@@ -307,7 +322,7 @@ where
         self.search_zero_layer(q, searcher, cap);
 
         let found = core::cmp::min(dest.len(), searcher.nearest.len());
-        dest.copy_from_slice(&searcher.nearest[..found]);
+        dest[..found].copy_from_slice(&searcher.nearest[..found]);
         &mut dest[..found]
     }