Handle invalid opacity

Author: jzempel

packages/theming/src/utils/getColor.spec.ts

@@ -354,5 +354,13 @@ describe('getColor', () => {
     it('throws an error if shade is invalid', () => {
       expect(() => getColor({ theme: DEFAULT_THEME, hue: 'blue', shade: NaN })).toThrow(TypeError);
     });
+
+    it('throws an error if transparency is invalid', () => {
+      const invalid = DEFAULT_THEME.opacity[100] + 1;
+
+      expect(() => getColor({ theme: DEFAULT_THEME, hue: 'blue', transparency: invalid })).toThrow(
+        Error
+      );
+    });
   });
 });

packages/theming/src/utils/getColor.ts

@@ -112,6 +112,10 @@ const toColor = (
   if (retVal && transparency) {
     const alpha = transparency > 1 ? opacity[transparency] : transparency;
 
+    if (alpha === undefined) {
+      throw new Error('Error: invalid `transparency` parameter');
+    }
+
     retVal = rgba(retVal, alpha);
   }