From 02d4c5f9def2be32a639d663db1d1ce5fcf16575 Mon Sep 17 00:00:00 2001
From: kevin <5299031+kevin9327@users.noreply.github.com>
Date: Fri, 30 Oct 2026 18:41:03 +0900
Subject: [PATCH] [babel-plugin] Drop floating-point noise when converting ms
 timings to seconds

---
 .../transform-value-normalization-test.js          | 14 ++++++++++++++
 .../src/shared/utils/normalizers/timings.js        |  4 +++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/packages/@stylexjs/babel-plugin/__tests__/transform-value-normalization-test.js b/packages/@stylexjs/babel-plugin/__tests__/transform-value-normalization-test.js
index 9ab0eb1d3..c63e867f1 100644
--- a/packages/@stylexjs/babel-plugin/__tests__/transform-value-normalization-test.js
+++ b/packages/@stylexjs/babel-plugin/__tests__/transform-value-normalization-test.js
@@ -278,6 +278,20 @@ describe('@stylexjs/babel-plugin', () => {
       `);
     });
 
+    test('timing values converted to seconds carry no floating-point noise', () => {
+      const output = transform(`
+        import stylex from 'stylex';
+        const styles = stylex.create({
+          x: { transitionDuration: '33.3ms' },
+          y: { animationDelay: '11.3ms' },
+          z: { transition: 'opacity 13.8ms ease-in 10.2ms' }
+        });
+      `);
+      expect(output).toContain('transition-duration:.0333s');
+      expect(output).toContain('animation-delay:.0113s');
+      expect(output).toContain('transition:opacity .0138s ease-in .0102s');
+    });
+
     test('transforms non-unitless property values', () => {
       expect(
         transform(`
diff --git a/packages/@stylexjs/babel-plugin/src/shared/utils/normalizers/timings.js b/packages/@stylexjs/babel-plugin/src/shared/utils/normalizers/timings.js
index 5bec8f2de..ce9c455cf 100644
--- a/packages/@stylexjs/babel-plugin/src/shared/utils/normalizers/timings.js
+++ b/packages/@stylexjs/babel-plugin/src/shared/utils/normalizers/timings.js
@@ -34,7 +34,9 @@ export default function normalizeTimings(
     if (!dimension || dimension.unit !== 'ms' || value < 10) {
       return;
     }
-    node.value = value / 1000 + 's';
+    // `33.3 / 1000` is 0.033299999999999996 in floating point; 15 significant
+    // digits drop that noise without losing any digit a CSS time can carry.
+    node.value = Number((value / 1000).toPrecision(15)) + 's';
   });
   return ast;
 }