如何将新项目“推”到数组中间？
这个问题在这里已经有了答案：
您可以使用Array.splice将项目插入到特定位置的Array中。
const suits = ["hearts", "clubs", "Brooks Brothers", "diamonds", "spades"];
suits.splice(2, 0, 'newItem');
console.log(suits);你应该使用拼接功能
arr.splice(index, 0, item); 将项目插入到指定索引的arr中（首先删除0个项目，即它只是一个插入）。
var suits = ["hearts","clubs","Brooks Brothers", "diamonds","spades"]
suits.splice(2, 0, "somevalue");
console.log(suits);您可以使用内置的接头功能
splice（）方法通过删除现有元素和/或添加新元素来更改数组的内容。
1-插入单个值
var suits = ["hearts","clubs","Brooks Brothers", "diamonds","spades"];
//1st param is insert index = 2 means insert at index 2
//2nd param is delete item count = 0 means delete 0 elements
//3rd param is new item that you want to insert
suits.splice(2, 0 , "Test");
console.log(suits);