fix: only refresh when slider still exists

Author: pimlie

lib/form-slider.js

@@ -36,9 +36,11 @@ export default {
     }
   },
   methods: {
-    refresh: throttle(function () {
-      this.slider.refresh({ useCurrentValue: true })
-      this.bindEvents()
+    refresh: throttle(function() {
+      if (this.slider) {
+        this.slider.refresh({ useCurrentValue: true })
+        this.bindEvents()
+      }
     }, 10),
     bindEvents() {
       const events = ['slide', 'slide-start', 'slide-stop', 'change', 'slide-enabled', 'slide-disabled']