From a5e9929d67fe9bdd4b07062eb3686a643515d8a3 Mon Sep 17 00:00:00 2001
From: overlookmotel <theoverlookmotel@gmail.com>
Date: Sat, 18 Jan 2025 00:01:48 +0000
Subject: [PATCH] perf(lexer): `finish_next` only clear `kind` and `flags`

---
 crates/oxc_parser/src/lexer/mod.rs   | 10 +++++-----
 crates/oxc_parser/src/lexer/token.rs |  8 ++++++++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/crates/oxc_parser/src/lexer/mod.rs b/crates/oxc_parser/src/lexer/mod.rs
index 02397fdd2bda7..261117521aebd 100644
--- a/crates/oxc_parser/src/lexer/mod.rs
+++ b/crates/oxc_parser/src/lexer/mod.rs
@@ -215,12 +215,12 @@ impl<'a> Lexer<'a> {
     }
 
     fn finish_next(&mut self, kind: Kind) -> Token {
-        self.token.kind = kind;
-        self.token.end = self.offset();
-        debug_assert!(self.token.start <= self.token.end);
-        let token = self.token;
+        let mut token = self.token;
+        token.kind = kind;
+        token.end = self.offset();
+        debug_assert!(token.start <= token.end);
         self.trivia_builder.handle_token(token);
-        self.token = Token::default();
+        self.token.clear_kind_and_flags();
         token
     }
 
diff --git a/crates/oxc_parser/src/lexer/token.rs b/crates/oxc_parser/src/lexer/token.rs
index 63e3a774b6e6c..ff404ab3ccc9c 100644
--- a/crates/oxc_parser/src/lexer/token.rs
+++ b/crates/oxc_parser/src/lexer/token.rs
@@ -62,6 +62,14 @@ impl Token {
         debug_assert!(!self.has_separator || self.kind.is_number() || self.kind == Kind::default());
         self.has_separator = true;
     }
+
+    #[inline]
+    pub fn clear_kind_and_flags(&mut self) {
+        self.kind = Kind::default();
+        self.is_on_new_line = false;
+        self.escaped = false;
+        self.has_separator = false;
+    }
 }
 
 #[cfg(test)]