From ef4c1f4e32f16eb3d2f71a8ac68a6cbdb1f9c403 Mon Sep 17 00:00:00 2001
From: overlookmotel <557937+overlookmotel@users.noreply.github.com>
Date: Fri, 12 Jul 2024 01:41:28 +0000
Subject: [PATCH] perf(semantic): reduce lookups (#4214)

Small performance optimization (I hope) to resolving references in `Semantic`. Look up current bindings once rather than on every turn of the loop.
---
 crates/oxc_semantic/src/builder.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/crates/oxc_semantic/src/builder.rs b/crates/oxc_semantic/src/builder.rs
index 98938fa02..4cd56c7d3 100644
--- a/crates/oxc_semantic/src/builder.rs
+++ b/crates/oxc_semantic/src/builder.rs
@@ -380,10 +380,11 @@ impl<'a> SemanticBuilder<'a> {
         let parent_refs = iter.nth(self.current_scope_depth - 1).unwrap();
         let current_refs = iter.next().unwrap();
 
+        let bindings = self.scope.get_bindings(self.current_scope_id);
         for (name, reference_ids) in current_refs.drain() {
             // Try to resolve a reference.
             // If unresolved, transfer it to parent scope's unresolved references.
-            if let Some(symbol_id) = self.scope.get_binding(self.current_scope_id, &name) {
+            if let Some(symbol_id) = bindings.get(&name).copied() {
                 for reference_id in &reference_ids {
                     self.symbols.references[*reference_id].set_symbol_id(symbol_id);
                 }