JS Array&map&reduce

    let transformedIngredients = Object.keys(props.ingredients)
                        .map(igKey => {
                            return [...Array(props.ingredients[igKey])]
                            .map((_, index) => {
                                return <BurgerIngredient key={igKey + index} type = {igKey} />;
                            })
                        }).reduce((arr,el) => {
                            return arr.concat(el);
                        },[]);
    if(transformedIngredients.length == 0){
        transformedIngredients = <p>Please, Start adding ingredients!</p>;
    }