Vue js 2 Error in render: “TypeError: Cannot read property 'term_id' of undefined”

Недавно начал изучать VueJS 2, и при создании фильтра для таксономий для wordpress темы столкнулся с такой проблемой

(Error in render:"TypeError: Cannot read property 'term_id' of undefined")

, то есть при фильтрации данных почему 'term_id' undefined.

JS файл

<pre>
    Vue.component('post-list',{
    template : '#post',
    data () {
        return {
            brands: [],
            types: [],
            products : [],
            search:'',
            category: 'All',
        }
    },
    mounted() {
        axios
            .get("http://newnevesteli/wp-json/wp/v2/productstax")
            .then(response => (this.brands = response.data));
        axios
            .get("http://newnevesteli/wp-json/wp/v2/typestax?per_page=100")
            .then(response => (this.types = response.data));
        axios
            .get("http://newnevesteli/wp-json/wp/v2/products/?per_page=40")
            .then(response => (this.products = response.data));
    },
    computed: {
        filteredPost: function () {
            let self = this;
            let category = self.category;
            if(category == "All") {
                return self.products
                    .filter((products) => {
                        return products.title.rendered.toLowerCase().match(this.search);
                    })
            } else {
                return self.products
                    .filter((products) => {
                        return products.title.rendered.toLowerCase().match(this.search);
                    })
                    .filter((products) => {
                        return products.tax_prod[0].term_id == this.category;
                    })
                    .filter((products) => {
                        return products.tax_type[0].term_id == this.category;
                    })
                }
        }
    }
});
new Vue({
    el: '#app',
    component: 'post-list'
});
</pre>

** PHP шаблон **

<pre>
<section class="pt30">
    <div class="container">
        <div id="app">
            <post-list></post-list>
        </div>
        <template id="post">
            <div>
                <div class="row">
                    <div class="col-sm-12">
                        <input type="text" v-model="search" placeholder="Search">
                    </div>
                    <div class="col-sm-3">
                        <div>
                            <input type="radio" value="All" id="All" v-model="category" checked name="taxonomy">
                            <label for="All">All</label>
                        </div>
                    </div>
                    <div class="col-sm-3">
                        <div v-for="brand in brands">
                            <input type="radio" :value="brand.id"  :id="brand.name" v-model="category" name="taxonomy">
                            <label :for="brand.name">{{brand.name}}</label>
                        </div>
                    </div>
                    <div class="col-sm-3">
                        <div v-for="type in types">
                            <input type="radio" :value="type.id"  :id="type.name" v-model="category" name="taxonomy">
                            <label :for="type.name">{{type.name}}</label>
                        </div>
                    </div>
                </div>
                <div>
                    <div v-for="post in filteredPost">
                        <div class="col-sm-3">
                            <a :href="post.link">{{post.title.rendered}}</a>
                        </div>
                    </div>
                </div>
            </div>
        </template>
    </div>
</section>
</pre>   

** function.php ** Функция которая добавляет нужные поля в WP REST API

<pre>
function prepare_rest($data, $post, $request) {
    $_data = $data->data;
    $tax_prod = wp_get_post_terms( $post->ID, 'productstax', array("fields" => "all") );
    $tax_type = wp_get_post_terms( $post->ID, 'typestax', array("fields" => "all") );
    $_data['tax_prod'] = $tax_prod;
    $_data['tax_type'] = $tax_type;
    $data->data = $_data;
    return $data;
}
add_filter('rest_prepare_products', 'prepare_rest', 10, 3);
?>
</pre>

JSON

Пример элемента которые приходят через REST API

    <pre>
[
    {
        "id": 5669,
        "date": "2017-09-15T16:18:29",
        "date_gmt": "2017-09-15T13:18:29",
        "guid": {
            "rendered": "http://newnevesteli/?post_type=products&#038;p=5669"
        },
        "modified": "2017-11-23T23:54:40",
        "modified_gmt": "2017-11-23T20:54:40",
        "slug": "nelda-2",
        "status": "publish",
        "type": "products",
        "link": "http://newnevesteli/products/nelda-2/",
        "title": {
            "rendered": "NELDA"
        },
        "content": {
            "rendered": "",
            "protected": false
        },
        "featured_media": 0,
        "template": "",
        "tags": [],
        "productstax": [
            87
        ],
        "typestax": [
            47
        ],
        "productcattax": [
            112
        ],
        "collectionstax": [
            86
        ],
        "tax_prod": [
            {
                "term_id": 87,
                "name": "Vestelli",
                "slug": "vestelli-2",
                "term_group": 0,
                "term_taxonomy_id": 87,
                "taxonomy": "productstax",
                "description": "",
                "parent": 0,
                "count": 66,
                "filter": "raw",
                "term_order": "5"
            }
        ],
        "tax_type": [
            {
                "term_id": 47,
                "name": "Пышные и А-Силует",
                "slug": "pishnie-i-a-siluet",
                "term_group": 0,
                "term_taxonomy_id": 47,
                "taxonomy": "typestax",
                "description": "",
                "parent": 0,
                "count": 65,
                "filter": "raw",
                "term_order": "0"
            }
        ],
        "_links": {
            "self": [
                {
                    "href": "http://newnevesteli/wp-json/wp/v2/products/5669"
                }
            ],
            "collection": [
                {
                    "href": "http://newnevesteli/wp-json/wp/v2/products"
                }
            ],
            "about": [
                {
                    "href": "http://newnevesteli/wp-json/wp/v2/types/products"
                }
            ],
            "version-history": [
                {
                    "href": "http://newnevesteli/wp-json/wp/v2/products/5669/revisions"
                }
            ],
            "wp:attachment": [
                {
                    "href": "http://newnevesteli/wp-json/wp/v2/media?parent=5669"
                }
            ],
            "wp:term": [
                {
                    "taxonomy": "post_tag",
                    "embeddable": true,
                    "href": "http://newnevesteli/wp-json/wp/v2/tags?post=5669"
                },
                {
                    "taxonomy": "productstax",
                    "embeddable": true,
                    "href": "http://newnevesteli/wp-json/wp/v2/productstax?post=5669"
                },
                {
                    "taxonomy": "typestax",
                    "embeddable": true,
                    "href": "http://newnevesteli/wp-json/wp/v2/typestax?post=5669"
                },
                {
                    "taxonomy": "productcattax",
                    "embeddable": true,
                    "href": "http://newnevesteli/wp-json/wp/v2/productcattax?post=5669"
                },
                {
                    "taxonomy": "collectionstax",
                    "embeddable": true,
                    "href": "http://newnevesteli/wp-json/wp/v2/collectionstax?post=5669"
                }
            ],
            "curies": [
                {
                    "name": "wp",
                    "href": "https://api.w.org/{rel}",
                    "templated": true
                }
            ]
        }
    },
]
</pre>