Tabs: Fixed issue where Promise rejection was hitting application (#14816)

packages/tabs/src/tabs.vue

@@ -92,11 +92,14 @@
         if (this.currentName !== value && this.beforeLeave) {
           const before = this.beforeLeave(value, this.currentName);
           if (before && before.then) {
-            before.then(() => {
-              changeCurrentName();
-
-              this.$refs.nav && this.$refs.nav.removeFocus();
-            });
+            before
+              .then(() => {
+                changeCurrentName();
+                this.$refs.nav && this.$refs.nav.removeFocus();
+              }, () => {
+                // https://github.com/ElemeFE/element/pull/14816
+                // ignore promise rejection in `before-leave` hook
+              });
           } else if (before !== false) {
             changeCurrentName();
           }