Add multiple toast notification and each one has it's own disappearance time with javascript

Question

I'm a student and it's my first time here !
So I'm trying to code a toast notification for the first time, here's mine : toast notification
The problem is, when I add several of them, after 5s, they go below everything. I wanted it to be like this but after they all disappeared. And I don't know how to add like a personal disappearance time to each of the toast notification. So when one disappears, the others are like that : problematic toast notifications
The container has to disappear because either way I can't click on the button add to cart that are below it.
Do you have an idea for how to fix this ? If you have any code advice too, don't hesitate to tell me !

Here's the code (a little chaotic because I tried to follow youtube videos and then add my own thing and then I tried to find a solution with Gemini (Google AI) so yeah... ) :

function toastNotification(msg) {
  const alertContainer = document.querySelector(".container-alert"); // Select the container
  const newAlert = document.createElement("div"); // Create a new alert element
  newAlert.classList.add("alert", "showAlert"); // Add necessary classes
  // ...
  const closeBtn = document.createElement("div");
  closeBtn.classList.add("close-btn");
  const closeIcon = document.createElement("i");
  closeIcon.classList.add("fas", "fa-times");
  closeBtn.appendChild(closeIcon);
  newAlert.appendChild(closeBtn);

  // Append the new alert to the container
  alertContainer.appendChild(newAlert);

  // Add animation for showing and hiding the alert
  newAlert.classList.add("show");

  alertContainer.style.zIndex = "9999";

  setTimeout(() => {
    newAlert.classList.remove("show");
    newAlert.classList.add("hide");

    // Remove the alert after hiding animation
    setTimeout(() => {
      alertContainer.removeChild(newAlert);
      alertContainer.style.zIndex = "-1";
    }, 5000);
  }, 5000);




  closeBtn.addEventListener("click", () => {
    newAlert.classList.remove("show");
    newAlert.classList.add("hide");

    // Immediately remove the alert if closed manually
    setTimeout(() => {
      alertContainer.removeChild(newAlert);
      alertContainer.style.zIndex = "-1";
    }, 5000);

  });
}

toastNotification("hello world")
setTimeout(() => toastNotification("hello world2"), 1000)

.container-alert {
  width: 30rem;
  position: fixed;
  right: 0;
  bottom: 0px;
  display: flex;
  align-items: center;
  justify-content: end;
  flex-direction: column;
  overflow: hidden;
  padding: 20px;
  z-index: -1;
}

.alert {
  overflow: hidden;
  opacity: 0;
  pointer-events: none;
  width: 27rem;
  height: 5rem;
  font-weight: 500;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.3);
  display: flex;
  align-items: center;
}

.alert.showAlert {
  opacity: 1;
  pointer-events: auto;
  background-color: #fff;
}

<div class="container-alert">
  <div class="alert hide">
    <svg xmlns="http://www.w3.org/2000/svg" width="1.5rem" height="1.5rem" viewBox="0 0 48 48">
               <defs>
                    <mask id="ipSCheckOne0">
                        <g fill="none" stroke-linejoin="round" stroke-width="4">
                            <path fill="#fff" stroke="#fff" d="M24 44a19.937 19.937 0 0 0 14.142-5.858A19.937 19.937 0 0 0 44 24a19.938 19.938 0 0 0-5.858-14.142A19.937 19.937 0 0 0 24 4A19.938 19.938 0 0 0 9.858 9.858A19.938 19.938 0 0 0 4 24a19.937 19.937 0 0 0 5.858 14.142A19.938 19.938 0 0 0 24 44Z"/>
                            <path stroke="#000" stroke-linecap="round" d="m16 24l6 6l12-12"/>
                        </g>
                    </mask>
               </defs>
               <path fill="#30d300" d="M0 0h48v48H0z" mask="url(#ipSCheckOne0)"/>
           </svg>

    <span class="msg"></span>

    <div class="close-btn">
      <span class="fas fa-times"></span>
    </div>
  </div>
</div>

Answer 1

I found the solution !
So when you call the toastNotification function, you make the z-index -1 a line after. Not in the function like I did. So I deleted the z-index line that was on the timeout and moved it where it should've been !

const cartButtons = document.querySelectorAll(".cart-button");
cartButtons.forEach(cartButton=>{
currentMsg = msg + "ajouté au panier !"
cartButton.addEventListener('click', ()=>{
    toastNotification(currentMsg);
    alertContainer.style.zIndex = "-1";
    });
});