fix: support optional props border tokens

.changeset/witty-glasses-hear.md

@@ -0,0 +1,5 @@
+---
+'style-dictionary': patch
+---
+
+Allow border type tokens to be empty, every property is optional.

__tests__/common/transforms.test.js

@@ -1170,6 +1170,10 @@ describe('common', () => {
           }),
         ).to.equal('5px dashed #000000');
       });
+
+      it('allows every property to be optional', () => {
+        expect(borderTransform({})).to.equal('solid');
+      });
     });
 
     describe('strokeStyle/css/shorthand', () => {

lib/common/transforms.js

@@ -1176,7 +1176,9 @@ export default {
       if (typeof style === 'object') {
         style = 'dashed';
       }
-      return `${width} ${style} ${color}`;
+      return `${width ? `${width} ` : ''}${style ? `${style}` : 'solid'}${
+        color ? ` ${color}` : ''
+      }`;
     },
   },