css-color-parser: fix normalization of hue to [0, 360] range when hue is not finite

Author: romainmenke

packages/css-color-parser/CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changes to CSS Color Parser
 
+### Unreleased (patch)
+
+- Fix normalization of `hue` to `[0, 360]` range when `hue` is not finite
+
 ### 4.1.6
 
 _June 14, 2026_

packages/css-color-parser/dist/index.mjs

@@ -4,6 +4,10 @@ import { toLowerCaseAZ } from '../util/to-lower-case-a-z';
 
 export function normalizeHue(token: CSSToken): TokenNumber | false {
 	if (isTokenNumber(token)) {
+		if (!Number.isNaN(token[4].value) && !Number.isFinite(token[4].value)) {
+			token[4].value = 0;
+		}
+
 		token[4].value = token[4].value % 360;
 		if (token[4].value < 0) {
 			token[4].value += 360;
@@ -38,6 +42,10 @@ export function normalizeHue(token: CSSToken): TokenNumber | false {
 				return false;
 		}
 
+		if (!Number.isNaN(token[4].value) && !Number.isFinite(token[4].value)) {
+			token[4].value = 0;
+		}
+
 		value = value % 360;
 		if (value < 0) {
 			value += 360;

packages/css-color-parser/src/functions/hue-normalize-channel-value.ts

@@ -275,6 +275,16 @@ assert.deepStrictEqual(
 	},
 );
 
+assert.deepStrictEqual(
+	color(parse('hsl(calc(infinity) 100% 50%)')),
+	{
+		colorNotation: 'hsl',
+		channels: [0, 100, 50],
+		alpha: 1,
+		syntaxFlags: new Set(['has-percentage-values']),
+	},
+);
+
 for (const a of ['lab', 'lch', 'oklab', 'oklch', 'rgb', 'hwb', 'hsl']) {
 	assert.deepStrictEqual(
 		color(parse(`lab(from ${a}(none none none) l a b)`)).channels,
@@ -324,3 +334,4 @@ for (const a of ['lab', 'lch', 'oklab', 'oklch', 'rgb', 'hwb', 'hsl']) {
 	);
 }
 
+