fix: object setter has no effect

Author: eps1lon

lib/CSSStyleDeclaration.js

@@ -35,9 +35,6 @@ CSSStyleDeclaration.prototype = {
    * Returns the empty string if the property has not been set.
    */
   getPropertyValue: function(name) {
-    if (name.indexOf('--') === 0 && this.hasOwnProperty(name)) {
-      return this[name];
-    }
     if (!this._values.hasOwnProperty(name)) {
       return '';
     }
@@ -60,18 +57,17 @@ CSSStyleDeclaration.prototype = {
       return;
     }
     var isCustomProperty = name.indexOf('--') === 0;
-    // custom properties are case-sensitive
-    var propertyName = isCustomProperty ? name : name.toLowerCase();
-    if (
-      !isCustomProperty &&
-      !allProperties.has(propertyName) &&
-      !allExtraProperties.has(propertyName)
-    ) {
+    if (isCustomProperty) {
+      this._setProperty(name, value, priority);
+      return;
+    }
+    var lowercaseName = name.toLowerCase();
+    if (!allProperties.has(lowercaseName) && !allExtraProperties.has(lowercaseName)) {
       return;
     }
 
-    this[propertyName] = value;
-    this._importants[propertyName] = priority;
+    this[lowercaseName] = value;
+    this._importants[lowercaseName] = priority;
   },
   _setProperty: function(name, value, priority) {
     if (value === undefined) {

lib/CSSStyleDeclaration.test.js

@@ -537,7 +537,7 @@ describe('CSSStyleDeclaration', () => {
     const style = new CSSStyleDeclaration();
     style['--baz'] = 'yellow';
 
-    expect(style.getPropertyValue('--baz')).toEqual('yellow');
+    expect(style.getPropertyValue('--baz')).toEqual('');
   });
 
   test('custom properties are case-sensitive', () => {