Fix lightness-notation crash with "number" option and single-digit percentage (#8661)

ybiquitous · web-flow · commit 7cfc5e5bd643 · 2025-07-09T19:11:41.000+09:00
diff --git a/.changeset/major-seals-bathe.md b/.changeset/major-seals-bathe.md
@@ -0,0 +1,5 @@
+---
+"stylelint": patch
+---
+
+Fixed: `lightness-notation` crash with `"number"` option and single-digit percentage
diff --git a/lib/rules/lightness-notation/__tests__/index.mjs b/lib/rules/lightness-notation/__tests__/index.mjs
@@ -214,6 +214,19 @@ testRule({
 				},
 			],
 		},
+		{
+			code: 'a { color: oklab(0 0.1 241) }',
+			fixed: 'a { color: oklab(0% 0.1 241) }',
+			fix: {
+				range: [17, 18],
+				text: '0%',
+			},
+			message: messages.expected('0', '0%'),
+			line: 1,
+			column: 18,
+			endLine: 1,
+			endColumn: 19,
+		},
 	],
 });
 
@@ -423,5 +436,31 @@ testRule({
 				},
 			],
 		},
+		{
+			code: 'a { color: oklab(5% -100% 0.4) }',
+			fixed: 'a { color: oklab(0.05 -100% 0.4) }',
+			fix: {
+				range: [17, 19],
+				text: '0.05',
+			},
+			message: messages.expected('5%', '0.05'),
+			line: 1,
+			column: 18,
+			endLine: 1,
+			endColumn: 20,
+		},
+		{
+			code: 'a { color: oklab(0% -100% 0.4) }',
+			fixed: 'a { color: oklab(0 -100% 0.4) }',
+			fix: {
+				range: [18, 19],
+				text: '',
+			},
+			message: messages.expected('0%', '0'),
+			line: 1,
+			column: 18,
+			endLine: 1,
+			endColumn: 20,
+		},
 	],
 });
diff --git a/lib/rules/lightness-notation/index.cjs b/lib/rules/lightness-notation/index.cjs
diff --git a/lib/rules/lightness-notation/index.mjs b/lib/rules/lightness-notation/index.mjs
@@ -139,9 +139,16 @@ function asNumber(value, func) {
 /**
  * @param {number} num
  * @param {string} value
+ * @returns {string}
  */
 function roundToNumberOfDigits(num, value) {
-	return num.toPrecision(value.length - 2);
+	if (num === 0) return '0';
+
+	const precision = value.replaceAll('%', '').replaceAll('.', '').length;
+
+	if (precision === 0) return `${num}`;
+
+	return num.toPrecision(precision).replace(/0+$/, ''); // trim trailing zeros
 }
 
 /**

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +"stylelint": patch
 +---
++
 +Fixed: `lightness-notation` crash with `"number"` option and single-digit percentage