From 4986151dda8c16d592cd2d3148aa1cc4a722ff3e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 21:24:06 +0900
Subject: [PATCH 01/15] Add whitespace module

---
 crates/swc_ecma_parser/src/lexer/mod.rs        | 1 +
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 1 +
 2 files changed, 2 insertions(+)
 create mode 100644 crates/swc_ecma_parser/src/lexer/whitespace.rs

diff --git a/crates/swc_ecma_parser/src/lexer/mod.rs b/crates/swc_ecma_parser/src/lexer/mod.rs
index 05b855f18a2b..06e8cefa1a7c 100644
--- a/crates/swc_ecma_parser/src/lexer/mod.rs
+++ b/crates/swc_ecma_parser/src/lexer/mod.rs
@@ -34,6 +34,7 @@ mod table;
 #[cfg(test)]
 mod tests;
 pub mod util;
+mod whitespace;
 
 pub(crate) type LexResult<T> = Result<T, Error>;
 
diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
new file mode 100644
index 000000000000..8b137891791f
--- /dev/null
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -0,0 +1 @@
+

From 1c209b661792c378e8553662a63f5da75a200a12 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 21:44:50 +0900
Subject: [PATCH 02/15] Use lookup table

---
 crates/swc_ecma_parser/src/lexer/util.rs      |  48 +++----
 .../swc_ecma_parser/src/lexer/whitespace.rs   | 121 ++++++++++++++++++
 2 files changed, 137 insertions(+), 32 deletions(-)

diff --git a/crates/swc_ecma_parser/src/lexer/util.rs b/crates/swc_ecma_parser/src/lexer/util.rs
index 7365d4b72432..d5585beb430d 100644
--- a/crates/swc_ecma_parser/src/lexer/util.rs
+++ b/crates/swc_ecma_parser/src/lexer/util.rs
@@ -12,7 +12,10 @@ use swc_common::{
 use swc_ecma_ast::Ident;
 use tracing::warn;
 
-use super::{comments_buffer::BufferedComment, input::Input, Char, LexResult, Lexer};
+use super::{
+    comments_buffer::BufferedComment, input::Input, whitespace::SkipWhitespace, Char, LexResult,
+    Lexer,
+};
 use crate::{
     error::{Error, SyntaxError},
     lexer::comments_buffer::BufferedCommentKind,
@@ -184,18 +187,20 @@ impl<'a> Lexer<'a> {
     /// See https://tc39.github.io/ecma262/#sec-white-space
     pub(super) fn skip_space<const LEX_COMMENTS: bool>(&mut self) -> LexResult<()> {
         loop {
-            let cur_b = self.input.cur_as_ascii();
+            let (offset, newline) = {
+                let mut skip = SkipWhitespace {
+                    input: self.input.as_str(),
+                    newline: false,
+                    offset: 0,
+                };
 
-            if matches!(cur_b, Some(b'\n' | b'\r')) {
-                self.input.bump();
-                self.state.had_line_break = true;
-                continue;
-            }
+                skip.scan();
 
-            if matches!(cur_b, Some(b'\x09' | b'\x0b' | b'\x0c' | b'\x20' | b'\xa0')) {
-                self.input.bump();
-                continue;
-            }
+                (skip.offset, skip.newline)
+            };
+
+            self.input.bump_bytes(offset);
+            self.state.had_line_break |= newline;
 
             if LEX_COMMENTS && self.input.is_byte(b'/') {
                 if self.peek() == Some('/') {
@@ -207,27 +212,6 @@ impl<'a> Lexer<'a> {
                 }
                 break;
             }
-
-            let c = self.cur();
-            let c = match c {
-                Some(v) => v,
-                None => break,
-            };
-
-            match c {
-                // white spaces
-                '\u{feff}' => {}
-                // line breaks
-                '\u{2028}' | '\u{2029}' => {
-                    self.state.had_line_break = true;
-                }
-
-                _ if c.is_whitespace() => {}
-
-                _ => break,
-            }
-
-            self.bump();
         }
 
         Ok(())
diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 8b137891791f..85f1633ef06d 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -1 +1,122 @@
+/// Returns true if it's done
+pub(super) type ByteHandler = Option<for<'aa> fn(&mut SkipWhitespace<'aa>) -> bool>;
 
+/// Lookup table for whitespace
+static BYTE_HANDLERS: [ByteHandler; 256] = [
+    //   0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F   //
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, SPC, ___, SPC, ___, ___, ___, // 0
+    ___, NLN, ___, ___, NLN, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 1
+    ___, SPC, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 2
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 3
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 4
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 5
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 6
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 7
+    UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // 8
+    UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // 9
+    UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // A
+    UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // B
+    UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // C
+    UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // D
+    UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // E
+    UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // F
+];
+
+/// Stop
+const ___: ByteHandler = None;
+
+/// Newline
+const NLN: ByteHandler = Some(|skip| {
+    skip.offset += 1;
+    skip.newline = true;
+
+    false
+});
+
+/// Space
+const SPC: ByteHandler = Some(|skip| {
+    skip.offset += 1;
+
+    false
+});
+
+/// Unicode
+const UNI: ByteHandler = Some(|skip| {
+    let s = unsafe {
+        // Safety: `skip.offset` is always valid
+        skip.input.get_unchecked(skip.offset..)
+    };
+
+    let (len, c) = unsafe {
+        // Safety: Byte handlers are called only when `skip.input` is not empty
+        s.char_indices().next().unwrap_unchecked()
+    };
+
+    match c {
+        // white spaces
+        '\u{feff}' => {}
+        // line breaks
+        '\u{2028}' | '\u{2029}' => {
+            skip.newline = true;
+        }
+
+        _ if c.is_whitespace() => {}
+
+        _ => return true,
+    }
+
+    skip.offset += len;
+
+    false
+});
+
+/// API is taked from oxc by Boshen (https://github.com/Boshen/oxc/pull/26)
+pub(super) struct SkipWhitespace<'a> {
+    pub input: &'a str,
+
+    /// Total offset
+    pub offset: usize,
+
+    /// Found newline
+    pub newline: bool,
+}
+
+macro_rules! unwind_loop {
+    ($e:expr) => {{
+        $e;
+        $e;
+        $e;
+        $e;
+        $e;
+        $e;
+        $e;
+        $e;
+    }};
+}
+
+impl SkipWhitespace<'_> {
+    pub fn scan(&mut self) {
+        let mut byte;
+
+        loop {
+            unwind_loop!({
+                byte = self.input.as_bytes().get(self.offset).copied();
+
+                if let Some(byte) = byte {
+                    let handler =
+                        unsafe { *(&BYTE_HANDLERS as *const ByteHandler).offset(byte as isize) };
+
+                    if let Some(handler) = handler {
+                        if handler(self) {
+                            return;
+                        }
+                    } else {
+                        return;
+                    }
+                } else {
+                    return;
+                }
+            })
+        }
+    }
+}

From 94212785ef6d239632e30c3bc834b46ccbf70d03 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 21:46:53 +0900
Subject: [PATCH 03/15] Fix

---
 crates/swc_ecma_parser/src/lexer/util.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/crates/swc_ecma_parser/src/lexer/util.rs b/crates/swc_ecma_parser/src/lexer/util.rs
index d5585beb430d..615a0150ffb3 100644
--- a/crates/swc_ecma_parser/src/lexer/util.rs
+++ b/crates/swc_ecma_parser/src/lexer/util.rs
@@ -210,8 +210,9 @@ impl<'a> Lexer<'a> {
                     self.skip_block_comment()?;
                     continue;
                 }
-                break;
             }
+
+            break;
         }
 
         Ok(())

From 4b7a1eac093c219c2648b2906abb1429f0de6ace Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 21:51:06 +0900
Subject: [PATCH 04/15] Fix tabelx

---
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 85f1633ef06d..20ad839489bf 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -6,7 +6,7 @@ static BYTE_HANDLERS: [ByteHandler; 256] = [
     //   0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F   //
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, SPC, ___, SPC, ___, ___, ___, // 0
     ___, NLN, ___, ___, NLN, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 1
-    ___, SPC, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 2
+    SPC, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 2
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 3
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 4
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 5

From 3e5cdb405d01d1f943c55b9cbbb072f01f50b3a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 21:59:10 +0900
Subject: [PATCH 05/15] Fix table

---
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 20ad839489bf..a578f9f3db97 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -4,8 +4,8 @@ pub(super) type ByteHandler = Option<for<'aa> fn(&mut SkipWhitespace<'aa>) -> bo
 /// Lookup table for whitespace
 static BYTE_HANDLERS: [ByteHandler; 256] = [
     //   0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F   //
-    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, SPC, ___, SPC, ___, ___, ___, // 0
-    ___, NLN, ___, ___, NLN, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 1
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, NLN, ___, SPC, NLN, ___, ___, // 0
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 1
     SPC, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 2
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 3
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 4
@@ -101,6 +101,7 @@ impl SkipWhitespace<'_> {
         loop {
             unwind_loop!({
                 byte = self.input.as_bytes().get(self.offset).copied();
+                dbg!(byte);
 
                 if let Some(byte) = byte {
                     let handler =

From 90970c73cd5d69cefebac77df6e4115cb558f9db Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 22:00:15 +0900
Subject: [PATCH 06/15] remove dbg

---
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index a578f9f3db97..3ec154fc4aad 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -101,7 +101,6 @@ impl SkipWhitespace<'_> {
         loop {
             unwind_loop!({
                 byte = self.input.as_bytes().get(self.offset).copied();
-                dbg!(byte);
 
                 if let Some(byte) = byte {
                     let handler =

From c5e92038a8289176bf06915dac57f2c929e38e2c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 22:04:07 +0900
Subject: [PATCH 07/15] Remove unwind

---
 .../swc_ecma_parser/src/lexer/whitespace.rs   | 38 ++++++-------------
 1 file changed, 12 insertions(+), 26 deletions(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 3ec154fc4aad..45095d14f51c 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -81,42 +81,28 @@ pub(super) struct SkipWhitespace<'a> {
     pub newline: bool,
 }
 
-macro_rules! unwind_loop {
-    ($e:expr) => {{
-        $e;
-        $e;
-        $e;
-        $e;
-        $e;
-        $e;
-        $e;
-        $e;
-    }};
-}
-
 impl SkipWhitespace<'_> {
+    #[inline(always)]
     pub fn scan(&mut self) {
         let mut byte;
 
         loop {
-            unwind_loop!({
-                byte = self.input.as_bytes().get(self.offset).copied();
-
-                if let Some(byte) = byte {
-                    let handler =
-                        unsafe { *(&BYTE_HANDLERS as *const ByteHandler).offset(byte as isize) };
-
-                    if let Some(handler) = handler {
-                        if handler(self) {
-                            return;
-                        }
-                    } else {
+            byte = self.input.as_bytes().get(self.offset).copied();
+
+            if let Some(byte) = byte {
+                let handler =
+                    unsafe { *(&BYTE_HANDLERS as *const ByteHandler).offset(byte as isize) };
+
+                if let Some(handler) = handler {
+                    if handler(self) {
                         return;
                     }
                 } else {
                     return;
                 }
-            })
+            } else {
+                return;
+            }
         }
     }
 }

From 1c486691573e722be295e7bb2cf94f42e987f8b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 22:05:18 +0900
Subject: [PATCH 08/15] Fix table

---
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 45095d14f51c..2f9a5cfb266e 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -4,7 +4,7 @@ pub(super) type ByteHandler = Option<for<'aa> fn(&mut SkipWhitespace<'aa>) -> bo
 /// Lookup table for whitespace
 static BYTE_HANDLERS: [ByteHandler; 256] = [
     //   0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F   //
-    ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, NLN, ___, SPC, NLN, ___, ___, // 0
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, SPC, NLN, ___, SPC, NLN, ___, ___, // 0
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 1
     SPC, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 2
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 3

From 231f13b53360def55923291cbcd4a32ece2c8b5d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 22:23:39 +0900
Subject: [PATCH 09/15] $@

---
 crates/swc_ecma_parser/scripts/instrument/bench.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/swc_ecma_parser/scripts/instrument/bench.sh b/crates/swc_ecma_parser/scripts/instrument/bench.sh
index 1f8c08c49775..e0b4d34c4903 100755
--- a/crates/swc_ecma_parser/scripts/instrument/bench.sh
+++ b/crates/swc_ecma_parser/scripts/instrument/bench.sh
@@ -4,4 +4,4 @@ set -eu
 export RUST_LOG=off
 export MIMALLOC_SHOW_STATS=1
 
-cargo profile instruments --release -t time --features tracing/release_max_level_info --features swc_common/concurrent --features swc_common/parking_lot --bench parser -- --bench --color
+cargo profile instruments --release -t time --features tracing/release_max_level_info --features swc_common/concurrent --features swc_common/parking_lot --bench parser -- --bench --color $@

From 9711ffc79039984594ce8557f2673cf909da8972 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 22:23:52 +0900
Subject: [PATCH 10/15] Use for loop

---
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 2f9a5cfb266e..f5c8deba1d0c 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -84,20 +84,11 @@ pub(super) struct SkipWhitespace<'a> {
 impl SkipWhitespace<'_> {
     #[inline(always)]
     pub fn scan(&mut self) {
-        let mut byte;
+        for &byte in self.input.as_bytes() {
+            let handler = unsafe { *(&BYTE_HANDLERS as *const ByteHandler).offset(byte as isize) };
 
-        loop {
-            byte = self.input.as_bytes().get(self.offset).copied();
-
-            if let Some(byte) = byte {
-                let handler =
-                    unsafe { *(&BYTE_HANDLERS as *const ByteHandler).offset(byte as isize) };
-
-                if let Some(handler) = handler {
-                    if handler(self) {
-                        return;
-                    }
-                } else {
+            if let Some(handler) = handler {
+                if handler(self) {
                     return;
                 }
             } else {

From 3a62f0ff281aaa690e4ae1c67ed81456415166d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 22:39:39 +0900
Subject: [PATCH 11/15] inline

---
 crates/swc_ecma_parser/src/lexer/util.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/crates/swc_ecma_parser/src/lexer/util.rs b/crates/swc_ecma_parser/src/lexer/util.rs
index 615a0150ffb3..d31fddc594bb 100644
--- a/crates/swc_ecma_parser/src/lexer/util.rs
+++ b/crates/swc_ecma_parser/src/lexer/util.rs
@@ -218,6 +218,7 @@ impl<'a> Lexer<'a> {
         Ok(())
     }
 
+    #[inline(never)]
     pub(super) fn skip_line_comment(&mut self, start_skip: usize) {
         let start = self.cur_pos();
         self.input.bump_bytes(start_skip);
@@ -267,6 +268,7 @@ impl<'a> Lexer<'a> {
     }
 
     /// Expects current char to be '/' and next char to be '*'.
+    #[inline(never)]
     pub(super) fn skip_block_comment(&mut self) -> LexResult<()> {
         let start = self.cur_pos();
 

From 532619ceea7bf8b6492eb56ffb49faa740788693 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Sat, 11 Mar 2023 23:05:28 +0900
Subject: [PATCH 12/15] Use return value

---
 .../swc_ecma_parser/src/lexer/whitespace.rs   | 21 +++++++------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index f5c8deba1d0c..70945db70017 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -1,5 +1,5 @@
 /// Returns true if it's done
-pub(super) type ByteHandler = Option<for<'aa> fn(&mut SkipWhitespace<'aa>) -> bool>;
+pub(super) type ByteHandler = Option<for<'aa> fn(&mut SkipWhitespace<'aa>) -> usize>;
 
 /// Lookup table for whitespace
 static BYTE_HANDLERS: [ByteHandler; 256] = [
@@ -27,18 +27,13 @@ const ___: ByteHandler = None;
 
 /// Newline
 const NLN: ByteHandler = Some(|skip| {
-    skip.offset += 1;
     skip.newline = true;
 
-    false
+    1
 });
 
 /// Space
-const SPC: ByteHandler = Some(|skip| {
-    skip.offset += 1;
-
-    false
-});
+const SPC: ByteHandler = Some(|_| 1);
 
 /// Unicode
 const UNI: ByteHandler = Some(|skip| {
@@ -62,12 +57,10 @@ const UNI: ByteHandler = Some(|skip| {
 
         _ if c.is_whitespace() => {}
 
-        _ => return true,
+        _ => return 0,
     }
 
-    skip.offset += len;
-
-    false
+    len
 });
 
 /// API is taked from oxc by Boshen (https://github.com/Boshen/oxc/pull/26)
@@ -88,9 +81,11 @@ impl SkipWhitespace<'_> {
             let handler = unsafe { *(&BYTE_HANDLERS as *const ByteHandler).offset(byte as isize) };
 
             if let Some(handler) = handler {
-                if handler(self) {
+                let delta = handler(self);
+                if delta == 0 {
                     return;
                 }
+                self.offset += delta;
             } else {
                 return;
             }

From e44706b9cf85fa63b7b22dfa0a337e7c3d39035a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 13 Mar 2023 16:06:40 +0900
Subject: [PATCH 13/15] Fix `scan`

---
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 70945db70017..4304661647f6 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -77,7 +77,13 @@ pub(super) struct SkipWhitespace<'a> {
 impl SkipWhitespace<'_> {
     #[inline(always)]
     pub fn scan(&mut self) {
-        for &byte in self.input.as_bytes() {
+        let mut byte;
+        loop {
+            byte = match self.input.as_bytes().get(self.offset).copied() {
+                Some(v) => v,
+                None => return,
+            };
+
             let handler = unsafe { *(&BYTE_HANDLERS as *const ByteHandler).offset(byte as isize) };
 
             if let Some(handler) = handler {

From df74d1b917e19ed7d99ec1840702286520006c1c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 13 Mar 2023 16:07:39 +0900
Subject: [PATCH 14/15] Fix

---
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 4304661647f6..313e00f563cb 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -42,9 +42,9 @@ const UNI: ByteHandler = Some(|skip| {
         skip.input.get_unchecked(skip.offset..)
     };
 
-    let (len, c) = unsafe {
+    let c = unsafe {
         // Safety: Byte handlers are called only when `skip.input` is not empty
-        s.char_indices().next().unwrap_unchecked()
+        s.chars().next().unwrap_unchecked()
     };
 
     match c {
@@ -60,7 +60,7 @@ const UNI: ByteHandler = Some(|skip| {
         _ => return 0,
     }
 
-    len
+    c.len_utf8()
 });
 
 /// API is taked from oxc by Boshen (https://github.com/Boshen/oxc/pull/26)

From 2ab9af3cfe8f02ff9cf6d029fbdc30e58bffb25d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 13 Mar 2023 16:11:40 +0900
Subject: [PATCH 15/15] Fix tabel

---
 crates/swc_ecma_parser/src/lexer/whitespace.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/swc_ecma_parser/src/lexer/whitespace.rs b/crates/swc_ecma_parser/src/lexer/whitespace.rs
index 313e00f563cb..a38cffa05a03 100644
--- a/crates/swc_ecma_parser/src/lexer/whitespace.rs
+++ b/crates/swc_ecma_parser/src/lexer/whitespace.rs
@@ -4,7 +4,7 @@ pub(super) type ByteHandler = Option<for<'aa> fn(&mut SkipWhitespace<'aa>) -> us
 /// Lookup table for whitespace
 static BYTE_HANDLERS: [ByteHandler; 256] = [
     //   0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F   //
-    ___, ___, ___, ___, ___, ___, ___, ___, ___, SPC, NLN, ___, SPC, NLN, ___, ___, // 0
+    ___, ___, ___, ___, ___, ___, ___, ___, ___, SPC, NLN, SPC, SPC, NLN, ___, ___, // 0
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 1
     SPC, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 2
     ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, ___, // 3