Can't check all checkboxes in Vue 3 - vue.js

Question

I am doing delete and delete multiple function for the table, I used the following code but it doesn't seem to work when I click all.
template:
<tr
v-if="isAdmin == 1"
v-for="(file, index) in files"
:key="index"
>
<td class="px-4 py-3">
<div class="flex items-center text-sm">
<div
>
<input
type="checkbox"
v-model="selected"
:value="file._id"
number
/>
</div>
<div>
<p class="font-semibold">{{ file.name }}</p>
</div>
</div>
</td>
<td class="px-4 py-3 text-sm">{{ file.size }} KB</td>
</tr>
And here is the script:
<script setup lang="ts">
const selected = ref([]);
const selectAll = computed({
get() {
return files.value ? selected.value.length == files.value.length : false;
},
set(value) {
let objnull: any = [];
let selected = [];
if (value) {
files.value.forEach((file) => {
selected.push(file._id);
});
}
selected = objnull;
},
});
</script>
Hope there is some solution for me, and I want to get the selected ids to call the api, thanks for everyone's help