修复bug

src/App.vue

@@ -104,8 +104,10 @@ export default {
     },
   },
   created () {
-    const { LoginError } = typeof this.systemSet === "string" ? JSON.parse(this.systemSet) : this.systemSet;
-    this.LoginError = LoginError;
+    if (this.systemSet) {
+      const { LoginError } = typeof this.systemSet === "string" ? JSON.parse(this.systemSet) : this.systemSet;
+      this.LoginError = LoginError;
+    }
   },
   mounted () {
     const num = Number(this.errorNum);