Circular items computed

formattedItems: {
            get() {
                let items = [];

                this.items.map(mapItem => mapItem.categories = this.optionsCategories);
                this.items.forEach((item, index, array) => {
                    array.forEach(el => {
                        if(el.id === item.id && el.category !== item.category) {
                            el.categories = el.categories.filter(category => category !== item.category);
                        }
                    });

                    items = [...array];
                });

                return items;
            }
        }