How I can make better this java script code:
```js
const observer = new MutationObserver(mutations => {
 mutations.forEach(mutation => {
 mutation.addedNodes.forEach(node => {
 if (node.matches && node.matches("avatar-card-container")) {
 const id = node.parentElement.id
 alert(id)
 }
 })
 })
})
observer.observe(document, {childList: true, subtree: true})
```
  There are a few things you can do to improve this code:

1. Use destructuring to simplify the `mutation.addedNodes` loop:
```js
const observer = new MutationObserver(mutations => {
  mutations.forEach(mutation => {
    const { addedNodes } = mutation
    addedNodes.forEach(node => {
      if (node.matches && node.matches("avatar-card-container")) {
        const id = node.parentElement.id
        alert(id)
      }
    })
  })
})
```
2. Use `node.closest()` instead of `node.matches()` to check if the node is a direct child of the `avatar-card-container` element:
```js
const observer = new MutationObserver(mutations => {
  mutations.forEach(mutation => {
    const { addedNodes } = mutation
    addedNodes.forEach(node => {
      if (node.closest("avatar-card-container")) {
        const id = node.parentElement.id
        alert(id)
      }
    })
  })
})
```
3. Use `document.querySelector()` instead of `document.getElementById()` to get the `avatar-card-container` element:
```js
const observer = new Mut
This Java script code can be improved by using a more specific selector for the element, such as "#avatar-card-container". This will help ensure that the observer is only triggered on the desired element.