feat(array): add reverse fast path

trynova · Oct 16, 2024 · e75d604 · e75d604
1 parent f5740ff
commit e75d604
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/nova_vm/src/ecmascript/builtins/indexed_collections/array_objects/array_prototype.rs b/nova_vm/src/ecmascript/builtins/indexed_collections/array_objects/array_prototype.rs
@@ -2089,6 +2089,15 @@ impl ArrayPrototype {
     }
 
     fn reverse(agent: &mut Agent, this_value: Value, _: ArgumentsList) -> JsResult<Value> {
+        if let Value::Array(array) = this_value {
+            // Fast path: Array is dense and contains no descriptors. No JS
+            // functions can thus be called by shift.
+            if array.is_trivial(agent) && array.is_dense(agent) {
+                array.as_mut_slice(agent).reverse();
+                return Ok(array.into_value());
+            }
+        }
+
         // 1. Let O be ? ToObject(this value).
         let o = to_object(agent, this_value)?;
         // 2. Let len be ? LengthOfArrayLike(O).