Why is using reverse in vue invalid?

The reasons why reverse in Vue is invalid include: looping objects, using non-responsive data, and non-unique key values. To solve this, convert the object to an array, use Vue.set to make the data responsive, and provide unique key values.

Why reverse is invalid in Vue

In Vue, the v-for directive A reverse option is provided, the purpose of which is to reverse the order of elements in the loop. However, sometimes using reverse may not work, causing the list elements to retain their original order.

Reason:

reverse option is only valid if:

• Loops over arrays or mutables Array (for example, the array bound by v-model).
• When looping over an object, the object has been converted to an array (for example, using Object.values or Object.keys).

Invalid situations:

reverse Invalid situations include:

• Loop an original object (instead of converting to an array).
• Loop over a non-reactive array or object.
• Use a non-unique key on the :key attribute of the v-for directive.

Solution:

To solve the problem of reverse failure, you can try the following methods:

• Confirm that the loop is an array or a variable array.
• If the loop is an object, please convert it into an array.
• Make sure that the :key attribute provides a unique key.
• If the array or object is non-reactive, use Vue.set to manually make it responsive.

Example:

If reverse is invalid and the loop is an object, you can convert it into an array before usingreverse：

<ul v-for="item in Object.values(obj)">
  <li>{{ item }}</li>
</ul>

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