Answers for "if doesnt contain in array then push"

js push into array if item exist

if(this.items.indexOf(item) === -1) {
    this.items.push(item);
    console.log(this.items);
}

array includes with or condition

if (['slug-title-one','slug-title-13'].some(slug => item.slug.includes(slug))) {
     // checks for and displays if either

}