fix: avoid evaluation error in isHTML computed prop

Author: setaman

src/App.vue

@@ -53,7 +53,11 @@
           :line-mode="lineMode"
           animation="default 1500 1000"
           :legend="-123.1"
-        ></ve-progress>
+        >
+          <template #legend-caption>
+            <p>hello</p>
+          </template>
+        </ve-progress>
       </div>
     </div>
   </div>

src/components/VueEllipseProgress.vue

@@ -62,7 +62,9 @@ export default {
       return this.data.length > 1;
     },
     isHTML() {
-      return /<[a-z/][\s\S]*>/i.test((this.legendFormatter(defaultCounterTick) || "").toString().trim());
+      return /<[a-z/][\s\S]*>/i.test(
+        ((this.legendFormatter && this.legendFormatter(defaultCounterTick)) || "").toString().trim()
+      );
     },
     circlesData() {
       if (this.isMultiple) {