Getting the dropdown to show based on an ID in vue - vue.js

Question

I have 2 pages, one has a list of products and the other one has a bunch of data for that product. There is also a drop-down in the second page.
The problem I'm having is that I'm struggling to get the drop-down to have the selected product selected.
So for example, if I select product 1 from the first page then on the second page the drop-down will show product 1 and if I select product 2 then the drop-down will show product 2.
Here is my code for productIndex.vue
<template>
<div>
<div class="content-header">
<div class="container">
<div class="row">
<div class="col-md-12">
<div class="card">
<div class="card-header">
<h3 class="card-title">Product Index</h3>
</div>
<div class="card-body p-0">
<table class="table table-sm table-hover">
<thead>
<tr>
<th>ID</th>
<th>Product Name</th>
<th style="width: 180px;"></th>
</tr>
</thead>
<tbody>
<tr v-for="product in products">
<td>{{ product.id }}</td>
<td>{{product.name}}</td>
<td class="text-right">
<a #click="goToProductData(product.id)" class="btn btn-xs btn-primary">
Data
</a>
</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</template>
<script>
export default {
props: ['products'],
data() {
return {
}
},
methods: {
goToProductData(product_id){
localStorage.setItem('product', product_id);
window.location = `/product-data`;
}
},
}
</script>
and here is my productData.vue
<template>
<div>
<div class="content-header">
<div class="container">
<div class="card">
<div class="card-body">
<div class="row mb-2">
<div class="col-sm-6">
<label for="product_id_select">Product</label>
<select id="product_id_select" class="form-control select2" style="width: 100%;">
<optgroup v-for="product in selectProducts" :label="customer.text">
<option v-for="p in product.children" :value="p.id">{{ p.text }}</option>
</optgroup>
</select>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</template>
<script>
export default {
props: ['products'],
data() {
return {
}
},
computed: {
selectProducts() {
let select2Options = [];
Object.keys(this.products).forEach(product => {
let productOptions = [];
this.products[product].forEach(p => {
productOptions.push({ id: p.id, text: p.name });
});
select2Options.push({
text: product,
children: productOptions
});
});
return select2Options;
}
}
}
</script>

Answer 1

You forgot to add the v-model to the select in the second page. You can find some example here.
Your code should be something like:
<select id="product_id_select" v-model="selectedProductId" class="form-control select2" style="width: 100%;">
where selectedProductId is a value in your data (or a computed property) that contains the value inserted into the local storage in the first page