perf(parser): add separate token kinds for BigInt literals (#14405)

## Summary

Add separate token kinds (`DecimalBigInt`, `BinaryBigInt`, `OctalBigInt`, `HexBigInt`) to eliminate the `ends_with('n')` string check when parsing BigInt literals.

Author: Boshen

crates/oxc_parser/src/js/expression.rs

@@ -270,14 +270,13 @@ impl<'a> ParserImpl<'a> {
                 let lit = self.parse_literal_null();
                 Expression::NullLiteral(self.alloc(lit))
             }
+            Kind::DecimalBigInt | Kind::BinaryBigInt | Kind::OctalBigInt | Kind::HexBigInt => {
+                let lit = self.parse_literal_bigint();
+                Expression::BigIntLiteral(self.alloc(lit))
+            }
             kind if kind.is_number() => {
-                if self.cur_src().ends_with('n') {
-                    let lit = self.parse_literal_bigint();
-                    Expression::BigIntLiteral(self.alloc(lit))
-                } else {
-                    let lit = self.parse_literal_number();
-                    Expression::NumericLiteral(self.alloc(lit))
-                }
+                let lit = self.parse_literal_number();
+                Expression::NumericLiteral(self.alloc(lit))
             }
             _ => self.unexpected(),
         }
@@ -342,17 +341,17 @@ impl<'a> ParserImpl<'a> {
         let token = self.cur_token();
         let kind = token.kind();
         let has_separator = token.has_separator();
-        let base = match kind {
-            Kind::Decimal => BigintBase::Decimal,
-            Kind::Binary => BigintBase::Binary,
-            Kind::Octal => BigintBase::Octal,
-            Kind::Hex => BigintBase::Hex,
+        let (base, number_kind) = match kind {
+            Kind::DecimalBigInt => (BigintBase::Decimal, Kind::Decimal),
+            Kind::BinaryBigInt => (BigintBase::Binary, Kind::Binary),
+            Kind::OctalBigInt => (BigintBase::Octal, Kind::Octal),
+            Kind::HexBigInt => (BigintBase::Hex, Kind::Hex),
             _ => return self.unexpected(),
         };
         let span = token.span();
         let raw = self.cur_src();
         let src = raw.strip_suffix('n').unwrap();
-        let value = parse_big_int(src, kind, has_separator, self.ast.allocator);
+        let value = parse_big_int(src, number_kind, has_separator, self.ast.allocator);
 
         self.bump_any();
         self.ast.big_int_literal(span, value, Some(Atom::from(raw)), base)

crates/oxc_parser/src/lexer/kind.rs

@@ -179,6 +179,11 @@ pub enum Kind {
     PositiveExponential,
     // for `1e-10`
     NegativeExponential,
+    // BigInt Literals (numeric literals with 'n' suffix)
+    DecimalBigInt,
+    BinaryBigInt,
+    OctalBigInt,
+    HexBigInt,
     // 12.9.4 String Literals
     /// String Type
     Str,
@@ -210,7 +215,17 @@ impl Kind {
     pub fn is_number(self) -> bool {
         matches!(
             self,
-            Float | Decimal | Binary | Octal | Hex | PositiveExponential | NegativeExponential
+            Float
+                | Decimal
+                | Binary
+                | Octal
+                | Hex
+                | PositiveExponential
+                | NegativeExponential
+                | DecimalBigInt
+                | BinaryBigInt
+                | OctalBigInt
+                | HexBigInt
         )
     }
 
@@ -660,6 +675,10 @@ impl Kind {
             Binary => "binary",
             Octal => "octal",
             Hex => "hex",
+            DecimalBigInt => "decimal bigint",
+            BinaryBigInt => "binary bigint",
+            OctalBigInt => "octal bigint",
+            HexBigInt => "hex bigint",
             Str | String => "string",
             RegExp => "/regexp/",
             NoSubstitutionTemplate => "${}",

crates/oxc_parser/src/lexer/numeric.rs

@@ -21,7 +21,7 @@ impl Lexer<'_> {
             }
             Some(b'n') => {
                 self.consume_char();
-                self.check_after_numeric_literal(Kind::Decimal)
+                self.check_after_numeric_literal(Kind::DecimalBigInt)
             }
             Some(n) if n.is_ascii_digit() => self.read_legacy_octal(),
             _ => self.check_after_numeric_literal(Kind::Decimal),
@@ -33,7 +33,7 @@ impl Lexer<'_> {
         if self.next_ascii_byte_eq(b'.') {
             return self.decimal_literal_after_decimal_point_after_digits();
         } else if self.next_ascii_byte_eq(b'n') {
-            return self.check_after_numeric_literal(Kind::Decimal);
+            return self.check_after_numeric_literal(Kind::DecimalBigInt);
         }
 
         let kind = self.optional_exponent().map_or(Kind::Decimal, |kind| kind);
@@ -78,8 +78,17 @@ impl Lexer<'_> {
                 _ => break,
             }
         }
-        self.next_ascii_byte_eq(b'n');
-        self.check_after_numeric_literal(kind)
+        let final_kind = if self.next_ascii_byte_eq(b'n') {
+            match kind {
+                Kind::Binary => Kind::BinaryBigInt,
+                Kind::Octal => Kind::OctalBigInt,
+                Kind::Hex => Kind::HexBigInt,
+                _ => unreachable!(),
+            }
+        } else {
+            kind
+        };
+        self.check_after_numeric_literal(final_kind)
     }
 
     fn read_legacy_octal(&mut self) -> Kind {