perf(mangler): reduce unnecessary allocation (#4498)

There seems to be no noticeable change in performance.
oxc-project · Jul 27, 2024 · 963a2d1 · 963a2d1
1 parent 5db7bed
commit 963a2d1
Showing 1 changed file with 6 additions and 7 deletions.
diff --git a/crates/oxc_mangler/src/lib.rs b/crates/oxc_mangler/src/lib.rs
@@ -105,8 +105,8 @@ impl ManglerBuilder {
 
             if !bindings.is_empty() {
                 // `bindings` are stored in order, traverse and increment slot
-                for symbol_id in bindings.values() {
-                    slots[*symbol_id] = slot;
+                for symbol_id in bindings.values().copied() {
+                    slots[symbol_id] = slot;
                     slot += 1;
                 }
             }
@@ -121,9 +121,6 @@ impl ManglerBuilder {
         let frequencies =
             Self::tally_slot_frequencies(&symbol_table, total_number_of_slots, &slots);
 
-        let unresolved_references =
-            scope_tree.root_unresolved_references().keys().collect::<Vec<_>>();
-
         let mut names = Vec::with_capacity(total_number_of_slots);
 
         let generate_name = if self.debug { debug_name } else { base54 };
@@ -133,7 +130,9 @@ impl ManglerBuilder {
                 let name = generate_name(count);
                 count += 1;
                 // Do not mangle keywords and unresolved references
-                if !is_keyword(&name) && !unresolved_references.iter().any(|n| **n == name) {
+                if !is_keyword(&name)
+                    && !scope_tree.root_unresolved_references().contains_key(name.as_str())
+                {
                     break name;
                 }
             });
@@ -169,7 +168,7 @@ impl ManglerBuilder {
             // sorting by slot enables us to sort by the order at which the vars first appear in the source
             // (this is possible because the slots are discovered currently in a DFS method which is the same order
             //  as variables appear in the source code)
-            symbols_renamed_in_this_batch.sort_by(|a, b| a.slot.cmp(&b.slot.clone()));
+            symbols_renamed_in_this_batch.sort_by(|a, b| a.slot.cmp(&b.slot));
 
             // here we just zip the iterator of symbols to rename with the iterator of new names for the next for loop
             let symbols_to_rename_with_new_names =