thank you for your previous help, now the toal quantity works perfectly. i have tried to aplly the same principle with the total price but it displays "nan" (" price += parseInt(monPanier[i].price);"). before adding this line, the total price diplayed was only one copy per item even eg there was two black items, 3 red items and 4 yellow, it was considered as total price one black + one red + one yellow. Thank you for your help.
let asynCompteur = 0;
let quantity = 0;
let price = 0;
for (let i = 0; i < monPanier.length; i++) {
fetch('http://localhost:3000/api/products/' + monPanier[i].id)/*appel de l'api*/
.then((reponse) => reponse.json())
.then((data) => {
/*asynCompteur pour réguler l'itération*/
asynCompteur = asynCompteur + 1;
//J'ajoute le prix et la quantité
quantity += parseInt(monPanier[i].quantity); price += data.price;
console.log('prix', asynCompteur, price, quantity);
price += parseInt(monPanier[i].price);
console.log(typeof monPanier[i].quantity);
if (asynCompteur === monPanier.length) {
document.querySelector("#totalQuantity").innerText = quantity;
document.querySelector("#totalPrice").innerText = price;
}it works partially. The quantity is updated correctly and follow the changes of the cart.So, the display of total quantity is correct.But... strangely, the total price consider only one of each item, it means: ie black item (2 times), yellow item (3 times), red item (2 times), total quantity displayd: 7 (correct), total price: incorrect(it displays total price of one black item + one yellow item + one red item. Thank you for your precious help.