Vue.js 如何将项目推送到 Vuejs 中数据对象的数组中 Vue 似乎没有关注 .push() 方法

我试图将对象添加到我在Vue实例数据对象中声明的数组中.我可以在州的purchase对象中设置值，但当我将数据推送到orders队列数组中时，空数组不会被填充.正在触发该函数，但数组不会更新.

这是我的表格:

<form
  v-on:submit.prevent="queuePurchase"
  class="form-inline row"
  id="order-creation-form"
  method="POST"
>

  @csrf
  <autocomplete-field
    sizing="col-xs-12 col-sm-3 col-md-3"
    name="customer"
    label="Customer"
    :data="{{ json_encode($customers) }}"
    v-on:setcustomer="setCustomer($event)"
  ></autocomplete-field>

  <div class="col-xs-12 col-sm-3 col-md3 form-group d-flex flex-column align-items-start">
    <label for="phone">Product</label>
    <select
      v-model="purchase.product"
      class="form-control w-100"
      name="product"
      aria-describedby="productHelpBlock"
      required
    >
      @foreach ($products as $product)
        <option :value="{{ json_encode($product) }}">
          {{ $product->name }}
        </option>
      @endforeach
    </select>
    <small id="productHelpBlock" class="form-text text-muted">
      Select a product
    </small>
  </div>

  <div class="col-xs-12 col-sm-3 col-md-3 form-group d-flex flex-column align-items-start">
    <label for="phone">Quantity</label>
    <input
      v-model="purchase.quantity"
      type="number"
      min="1"
      name="product"
      class="form-control w-100"
      aria-describedby="productHelpBlock"
      required
    >
    <small id="productHelpBlock" class="form-text text-muted">
      Product quantity
    </small>
  </div>

  <div class="form-group">
    <button type="submit" class="btn btn-success icon-button d-flex">
      <i class="material-icons">add</i>
      <span>&nbsp;&nbsp;  Q U E U E</span>
    </button>
  </div>
</form>

下面是我的javascript:

require("./bootstrap");
window.Vue = require("vue");

Vue.component("queue-table", require('./components/QueueTable.vue'));
Vue.component("autocomplete-field", require('./components/AutocompleteField.vue'));

const purchaseApp = new Vue({
    el: "#purchase-app",

    data() {
        return {
            queue: [],
            purchase: {
                product: null,
                customer: null,
                quantity: null
            }
        }
    },

    methods: {
        setCustomer: function(customerObj) {
            this.purchase.customer = customerObj;
        },

        queuePurchase: function() {
            this.queue.push( this.purchase );
        }
    }
});

有人能解释一下什么&amp；为什么会这样？