问“NodeListOf<Element>”类型的参数不能分配给“Node”类型的参数EN这个方法有效的原因是：向容量为零的切片追加元素将分配一个新的底层数组。函数体的长度最终比函数签名的长度要短，函数体短是一方面原因，函数签名长是另一方面原因。在本博客文章中，我们将解释为什么函数签名被写成这样。
Currently, the following DOM methods has a return type definition of NodeList, but the type of nodes returned is actually always Element: getElementsByClassName getElementsByTagNameNS getElementsByTagName(name: string) getElementsByName ...
The node at the specified position in the NodeList, ornullifindexis less than zero or greater than or equal to the length of the NodeList. Description This method returns the specified element of a NodeList. In JavaScript, you can use the square-bracket array notation instead of callingitem(...