I’m trying to do some simple form validation using Laravel 5.3 and Vue.js. Laravel controller: Vue data: Vue post: I’m getting TypeError: can’t assign to properties of (new String(“errors”)): not an object with app.$set(‘errors’, response.data); Where am I going wrong? Answer Check vm.$set(object, key, value), you’re trying to add a property to the string ‘errors’ using response.data as the key.