vue $set

html

<input
          @click="showPickerFun()"
          class="inputText"
          type="text"
          v-model="customer.orderTime"
          readonly
        >

data() {
    return {
      customer: {}
    };
  },

methods

methods: {
onSelect: (selectedTime, selectedText, formatedTime) => {
          this.$set(this.customer, "orderTime", `${formatedTime}`);
        }
}

正确书写规则；

1.数组===> this.$set( Array, index , value)

2.对象===>this.$set(Object,''key'',value)