Filtering a list of objects in Vue without altering the original data - vue.js

Question

I am diving into Vue for the first time and trying to make a simple filter component that takes a data object from an API and filters it.
The code below works but i cant find a way to "reset" the filter without doing another API call, making me think im approaching this wrong.
Is a Show/hide in the DOM better than altering the data object?
HTML
<button v-on:click="filterCats('Print')">Print</button>
<div class="list-item" v-for="asset in filteredData">
<a>{{ asset.title.rendered }}</a>
</div>
Javascript
export default {
data() {
return {
assets: {}
}
},
methods: {
filterCats: function (cat) {
var items = this.assets
var result = {}
Object.keys(items).forEach(key => {
const item = items[key]
if (item.cat_names.some(cat_names => cat_names === cat)) {
result[key] = item
}
})
this.assets = result
}
},
computed: {
filteredData: function () {
return this.assets
}
},
}

Answer 1

Is a Show/hide in the DOM better than altering the data object?
Not at all. Altering the data is the "Vue way".
You don't need to modify assets to filter it.
The recommended way of doing that is using a computed property: you would create a filteredData computed property that depends on the cat data property. Whenever you change the value of cat, the filteredData will be recalculated automatically (filtering this.assets using the current content of cat).
Something like below:
new Vue({
el: '#app',
data() {
return {
cat: null,
assets: {
one: {cat_names: ['Print'], title: {rendered: 'one'}},
two: {cat_names: ['Two'], title: {rendered: 'two'}},
three: {cat_names: ['Three'], title: {rendered: 'three'}}
}
}
},
computed: {
filteredData: function () {
if (this.cat == null) { return this.assets; } // no filtering
var items = this.assets;
var result = {}
Object.keys(items).forEach(key => {
const item = items[key]
if (item.cat_names.some(cat_names => cat_names === this.cat)) {
result[key] = item
}
})
return result;
}
},
})
<script src="https://unpkg.com/vue"></script>
<div id="app">
<button v-on:click="cat = 'Print'">Print</button>
<div class="list-item" v-for="asset in filteredData">
<a>{{ asset.title.rendered }}</a>
</div>
</div>