[英]How do I push items into an array in the data object in Vuejs? Vue seems not to be watching the .push() method
I am attempting to add objects into an array I declared in Vue instance data object. 我试图将对象添加到在Vue实例数据对象中声明的数组中。 I can set the values in the state's purchase object, but when I push data into the orders queue array, the empty array is not populated. 我可以在州的购买对象中设置值,但是当我将数据推入订单队列数组时,不会填充空数组。 The function is being triggered, but the array does not update. 该函数正在被触发,但是数组未更新。
Here is my form: 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> Q U E U E</span>
</button>
</div>
</form>
And here is my javascript: 这是我的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 );
}
}
});
Could someone please explain what & why it is happening? 有人可以解释一下发生的原因吗?
The push()
method ought to add purchase
objects to the queue
array, but as @FK82 pointed out in his comment, push()
is adding multiple references to the same purchase
object. push()
方法应该将purchase
对象添加到queue
数组,但是正如@ FK82在他的评论中指出的那样, push()
正在向同一purchase
对象添加多个引用。 This means that if you change the object by increasing the quantity
, every purchase
's quantity
property will be updated. 这意味着,如果您通过增加quantity
更改对象,则每个purchase
的quantity
属性将被更新。
You can give that a try here: 您可以在这里尝试一下:
const exampleComponent = Vue.component("example-component", { name: "exampleComponent", template: "#example-component", data() { return { queue: [], purchase: { product: null, customer: null, quantity: null } }; }, methods: { queuePurchase() { this.queue.push( this.purchase ); } } }); const page = new Vue({ name: "page", el: ".page", components: { "example-component": exampleComponent } });
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.2.4/vue.min.js"></script> <template id="example-component"> <div> <p>The Queue has {{ this.queue.length }} items.</p> <input v-model="purchase.quantity" type="number" min="1" name="product" placeholder="Quantity" > <button @click="queuePurchase"> Add to Queue </button> <pre>{{ JSON.stringify(this.queue, null, 2) }}</pre> </div> </template> <div class="page"> <example-component></example-component> </div>
Instead of push()
ing a reference to the same purchase
object, try creating a shallow copy with Object.assign({}, this.purchase)
or by using the spread operator. 与其使用push()
引用对同一purchase
对象的引用Object.assign({}, this.purchase)
尝试使用Object.assign({}, this.purchase)
或使用散布运算符创建浅表副本。 Here's an example that uses the spread operator and then push()
es the copy onto the queue
: 这是一个使用spread运算符,然后push()
副本push()
es放入queue
的示例:
const exampleComponent = Vue.component("example-component", { name: "exampleComponent", template: "#example-component", data() { return { queue: [], purchase: { product: null, customer: null, quantity: null } }; }, methods: { queuePurchase() { this.queue.push({...this.purchase}); } } }); const page = new Vue({ name: "page", el: ".page", components: { "example-component": exampleComponent } });
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.2.4/vue.min.js"></script> <template id="example-component"> <div> <p>The Queue has {{ this.queue.length }} items.</p> <input v-model="purchase.quantity" type="number" min="1" name="product" placeholder="Quantity" > <button @click="queuePurchase"> Add to Queue </button> <pre>{{ JSON.stringify(this.queue, null, 2) }}</pre> </div> </template> <div class="page"> <example-component></example-component> </div>
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.