From bc302f4f8bbc893c0c69f61d59a43d8e4ccc5db2 Mon Sep 17 00:00:00 2001
From: Boshen <boshenc@gmail.com>
Date: Thu, 16 Nov 2023 19:04:12 +0800
Subject: [PATCH] feat(prettier): print big int with lowercase (#1351)

---
 crates/oxc_prettier/src/format/mod.rs       | 8 +++++++-
 tasks/prettier_conformance/prettier.snap.md | 3 +--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/crates/oxc_prettier/src/format/mod.rs b/crates/oxc_prettier/src/format/mod.rs
index b055a4a9b..c0902766f 100644
--- a/crates/oxc_prettier/src/format/mod.rs
+++ b/crates/oxc_prettier/src/format/mod.rs
@@ -613,7 +613,13 @@ impl<'a> Format<'a> for NumberLiteral<'a> {
 
 impl<'a> Format<'a> for BigintLiteral {
     fn format(&self, p: &mut Prettier<'a>) -> Doc<'a> {
-        Doc::Str(self.span.source_text(p.source_text))
+        let text = self.span.source_text(p.source_text);
+        // Perf: avoid a memory allocation from `to_ascii_lowercase`.
+        if text.contains(|c: char| c.is_lowercase()) {
+            p.str(&text.to_ascii_lowercase())
+        } else {
+            Doc::Str(text)
+        }
     }
 }
 
diff --git a/tasks/prettier_conformance/prettier.snap.md b/tasks/prettier_conformance/prettier.snap.md
index 4fd61cb61..2d239d538 100644
--- a/tasks/prettier_conformance/prettier.snap.md
+++ b/tasks/prettier_conformance/prettier.snap.md
@@ -1,4 +1,4 @@
-Compatibility: 8/173 (4.62%)
+Compatibility: 9/173 (5.20%)
 
 # Failed
 
@@ -13,7 +13,6 @@ Compatibility: 8/173 (4.62%)
 * async
 * async-do-expressions
 * babel-plugins
-* big-int
 * binary-expressions
 * binary_math
 * bind-expressions