Answers for "javascript array if not exists push"

js push into array if item exist

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

js add to array if not exists

var newItem = "NEW_ITEM_TO_ARRAY";
var array = ["OLD_ITEM_1", "OLD_ITEM_2"];

array.indexOf(newItem) === -1 ? array.push(newItem) : console.log("This item already exists");

console.log(array)