Question 190905 in Javascript Question posted in
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Javascript – one code works and the other doesn't in alpine.js

    @{
    int MOOD = 167;
}
<div x-data="{  variants: [] }" x-init="fetchVariants()" x-bind:data-product-id="@MOOD">

    <!-- Trigger for Modal -->
    <div x-text="JSON.stringify(variants)"></div>
    </div>
  
<script>
    function fetchVariants() {
        const productId = document.querySelector('[x-bind\:data-product-id]').getAttribute('data-product-id');
        const url = `/Home/ProductDesc?ProductId=${productId}`;

        fetch(url)
            .then(res => res.json())
            .then(res => {
                variants = res.variant.map(item => ({ price: item.price }));
                // Update the variants property with the new array of prices
               Alpine.store('variants', variants);

      //          console.log();
            })
            .catch(error => {
                console.error('Error:', error);
            });
    }
</script>




<div x-data="{
    variants: []
  }"
     x-init="fetch('/Home/ProductDesc?ProductId=167')
     .then(res=>res.json())
    .then(res => {
    variants = res.variant.map(item => ({ price: item.price }));
    })"
    >
    <div x-text="JSON.stringify(variants)"></div>
</div>

the both code are same in my view but the above code doesn’t work and the below code works ? what could be wrong as the above code is also same in my view.

Tags:

3

Answers


  1. Chosen as BEST ANSWER
    0

    this worked for me

    @{
    int MOOD = 167;
}
<div x-data="{  variants: [] }" x-init="fetchVariants" x-bind:data-product-id="@MOOD">

    <!-- Trigger for Modal -->
    <div x-text="JSON.stringify(variants)"></div>
    </div>
  
<script>
    function fetchVariants() {
        const productId = document.querySelector('[x-bind\:data-product-id]').getAttribute('data-product-id');
        const url = `/Home/ProductDesc?ProductId=${productId}`;

        fetch(url)
            .then(res => res.json())
            .then((variants) => {
                this.variants = variants;
            })
            .catch(error => {
                console.error('Error:', error);
            });
    }
</script>

    it outputted which was non existence

    this also worked

    <div x-data="{ data: null }">
<button @@click="fetchData">Fetch Data</button>

<div x-text="JSON.stringify(data.title)">
</div>

    <script>
    function fetchData() {
        fetch('/home/getdata')
            .then(response => response.json())
            .then((data) => {
                this.data = data; // Assign the fetched data to Alpine.js data property
                console.log(data);
            })
            .catch(error => {
                console.error('Error fetching data:', error);
            });
    }

    </script>

  2. 0

    The two code snippets you provided are similar in structure, but there is a subtle difference in how the variants data property is updated. Let’s break down the difference:

    First code snippet:

    kotlin

    x-data="{  variants: [] }" x-init="fetchVariants()" x-bind:data-product-id="@MOOD"
The x-data directive initializes the variants property as an empty array. The x-init directive calls the fetchVariants function, which retrieves the data asynchronously and updates the variants property using Alpine.store('variants', variants).

    Second code snippet:

    kotlin
Copy code
x-data="{
  variants: []
}"
x-init="
  fetch('/Home/ProductDesc?ProductId=167')
    .then(res => res.json())
    .then(res => {
      variants = res.variant.map(item => ({ price: item.price }));
    })
"

    In this code, the fetch request is made directly within the x-init directive. The resulting JSON response is parsed, and the variants property is updated directly within the promise chain: variants = res.variant.map(item => ({ price: item.price }));.

    The difference between the two snippets lies in how the variants property is updated. In the first snippet, Alpine.store(‘variants’, variants) is used to update the property, while in the second snippet, variants = res.variant.map(item => ({ price: item.price })); directly assigns the new value to variants.

    The issue with the first code snippet is that it uses Alpine.store to update the variants property, but it doesn’t exist in the code. To fix it, you can modify the first snippet to update the variants property directly, similar to the second snippet:

    php

    <div x-data="{ variants: [] }" x-init="fetchVariants()" x-bind:data-product-id="@MOOD">
    <!-- Trigger for Modal -->
    <div x-text="JSON.stringify(variants)"></div>
</div>

<script>
    function fetchVariants() {
        const productId = document.querySelector('[x-bind\:data-product-id]').getAttribute('data-product-id');
        const url = `/Home/ProductDesc?ProductId=${productId}`;

        fetch(url)
            .then(res => res.json())
            .then(res => {
                this.variants = res.variant.map(item => ({ price: item.price }));
            })
            .catch(error => {
                console.error('Error:', error);
            });
    }
</script>

    In the modified code, the variants property is updated directly using this.variants = res.variant.map(item => ({ price: item.price })); inside the fetchVariants function.

    By making this change, the first code snippet should work as intended and populate the variants property with the retrieved data.

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  3. 0

    The global Alpine.store() object and the local x-data have different contexts. They serve different purpose. The global store object is good if you need to access/mutate some common data from multiple components. With x-data you create local properties that are accessible only for the component itself and all child components. But sibling components cannot access each other properties directly.

    With this knowledge one can answer your scoping question. In the first version you have a local property: variants. In x-init you call fetchVariants() that fetches the data and put it inside an Alpine.store object. And we already know that these are different variables, so the local variants defined in x-data remains an empty array. You can fix this version if you use $store.variants in the template.

    In your second example you use the local variants in the x-init not a new Alpine.store property, so this variable receives the new data and Alpine renders it in the template.

    Edit: small example for $store:

    <script defer src="https://cdn.jsdelivr.net/npm/[email protected]/dist/cdn.min.js"></script>

<script>
document.addEventListener('alpine:init', () => {
  Alpine.store('variants', [1,2,3])
})
</script>

<div x-data x-text="JSON.stringify($store.variants)"></div>
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