Always return arrays from parsePropertyValue

The inArray parameter caused cache thrashing: CSSStyleDeclaration.js called without it (caching strings) while property files called with inArray: true (expecting arrays). When the cached type didn't match what a caller needed, it would recompute and overwrite, causing the next different-type caller to also miss. By always returning arrays, all callers can share the same cached results.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: domenic

lib/parsers.js

@@ -252,7 +252,7 @@ const resolveCalc = (val, opt = { format: "specifiedValue" }) => {
  * @returns {string|Array<object>|undefined} The parsed value.
  */
 const parsePropertyValue = (prop, val, opt = {}) => {
-  const { caseSensitive, inArray } = opt;
+  const { caseSensitive } = opt;
   val = prepareValue(val);
   if (val === "" || hasVarFunc(val)) {
     return val;
@@ -269,38 +269,26 @@ const parsePropertyValue = (prop, val, opt = {}) => {
   const cachedValue = lruCache.get(cacheKey);
   if (cachedValue === false) {
     return;
-  } else if (inArray) {
-    if (Array.isArray(cachedValue)) {
-      return cachedValue;
-    }
-  } else if (typeof cachedValue === "string") {
+  } else if (cachedValue !== undefined) {
     return cachedValue;
   }
   let parsedValue;
   const lowerCasedValue = asciiLowercase(val);
   if (GLOBAL_KEYS.has(lowerCasedValue)) {
-    if (inArray) {
+    parsedValue = [
+      {
+        type: AST_TYPES.GLOBAL_KEYWORD,
+        name: lowerCasedValue
+      }
+    ];
+  } else if (SYS_COLORS.has(lowerCasedValue)) {
+    if (/^(?:(?:-webkit-)?(?:[a-z][a-z\d]*-)*color|border)$/i.test(prop)) {
       parsedValue = [
         {
-          type: AST_TYPES.GLOBAL_KEYWORD,
+          type: AST_TYPES.IDENTIFIER,
           name: lowerCasedValue
         }
       ];
-    } else {
-      parsedValue = lowerCasedValue;
-    }
-  } else if (SYS_COLORS.has(lowerCasedValue)) {
-    if (/^(?:(?:-webkit-)?(?:[a-z][a-z\d]*-)*color|border)$/i.test(prop)) {
-      if (inArray) {
-        parsedValue = [
-          {
-            type: AST_TYPES.IDENTIFIER,
-            name: lowerCasedValue
-          }
-        ];
-      } else {
-        parsedValue = lowerCasedValue;
-      }
     } else {
       parsedValue = false;
     }
@@ -312,7 +300,7 @@ const parsePropertyValue = (prop, val, opt = {}) => {
       const { error, matched } = cssTree.lexer.matchProperty(prop, ast);
       if (error || !matched) {
         parsedValue = false;
-      } else if (inArray) {
+      } else {
         const obj = cssTree.toPlainObject(ast);
         const items = obj.children;
         const values = [];
@@ -391,8 +379,6 @@ const parsePropertyValue = (prop, val, opt = {}) => {
           }
         }
         parsedValue = values;
-      } else {
-        parsedValue = val;
       }
     } catch {
       parsedValue = false;

lib/properties/backgroundAttachment.js

@@ -14,8 +14,7 @@ module.exports.parse = (v, opt = {}) => {
   const parsedValues = [];
   for (const val of values) {
     const value = parsers.parsePropertyValue(property, val, {
-      globalObject,
-      inArray: true
+      globalObject
     });
     if (Array.isArray(value) && value.length === 1) {
       const parsedValue = parsers.resolveKeywordValue(value);

lib/properties/backgroundClip.js

@@ -14,8 +14,7 @@ module.exports.parse = (v, opt = {}) => {
   const parsedValues = [];
   for (const val of values) {
     const value = parsers.parsePropertyValue(property, val, {
-      globalObject,
-      inArray: true
+      globalObject
     });
     if (Array.isArray(value) && value.length === 1) {
       const parsedValue = parsers.resolveKeywordValue(value);

lib/properties/backgroundColor.js

@@ -11,8 +11,7 @@ module.exports.parse = (v, opt = {}) => {
     return v;
   }
   const value = parsers.parsePropertyValue(property, v, {
-    globalObject,
-    inArray: true
+    globalObject
   });
   if (Array.isArray(value) && value.length === 1) {
     return parsers.resolveColorValue(value);

lib/properties/backgroundImage.js

@@ -14,8 +14,7 @@ module.exports.parse = (v, opt = {}) => {
   const parsedValues = [];
   for (const val of values) {
     const value = parsers.parsePropertyValue(property, val, {
-      globalObject,
-      inArray: true
+      globalObject
     });
     if (Array.isArray(value) && value.length === 1) {
       const parsedValue = parsers.resolveGradientUrlValue(value);

lib/properties/backgroundOrigin.js

@@ -14,8 +14,7 @@ module.exports.parse = (v, opt = {}) => {
   const parsedValues = [];
   for (const val of values) {
     const value = parsers.parsePropertyValue(property, val, {
-      globalObject,
-      inArray: true
+      globalObject
     });
     if (Array.isArray(value) && value.length === 1) {
       const parsedValue = parsers.resolveKeywordValue(value);

lib/properties/backgroundPosition.js

@@ -22,8 +22,7 @@ module.exports.parse = (v, opt = {}) => {
   const parsedValues = [];
   for (const val of values) {
     const value = parsers.parsePropertyValue(property, val, {
-      globalObject,
-      inArray: true
+      globalObject
     });
     if (Array.isArray(value) && value.length) {
       const [part1, part2, part3, part4] = value;

lib/properties/backgroundRepeat.js

@@ -17,8 +17,7 @@ module.exports.parse = (v, opt = {}) => {
   const parsedValues = [];
   for (const val of values) {
     const value = parsers.parsePropertyValue(property, val, {
-      globalObject,
-      inArray: true
+      globalObject
     });
     if (Array.isArray(value) && value.length) {
       let parsedValue = "";

lib/properties/backgroundSize.js

@@ -17,8 +17,7 @@ module.exports.parse = (v, opt = {}) => {
   const parsedValues = [];
   for (const val of values) {
     const value = parsers.parsePropertyValue(property, val, {
-      globalObject,
-      inArray: true
+      globalObject
     });
     if (Array.isArray(value) && value.length) {
       if (value.length === 1) {

lib/properties/border.js

@@ -45,8 +45,7 @@ module.exports.parse = (v, opt = {}) => {
   const parsedValues = new Map();
   for (const val of values) {
     const value = parsers.parsePropertyValue(property, val, {
-      globalObject,
-      inArray: true
+      globalObject
     });
     if (Array.isArray(value) && value.length === 1) {
       const parsedValue = parsers.resolveBorderShorthandValue(value, subProps, parsedValues);