var colors=["red","blue"];
var index=1;
//insert "white" at index 1
colors.splice(index, 0, "white"); //colors = ["red", "white", "blue"]
var fruits = ["222", "vvvv", "eee", "eeee"];
fruits.push("Kiwi");
var list = ["foo", "bar"];
list.push("baz");
["foo", "bar", "baz"] // result
const items = [1, 2, 3, 4, 5]
const insert = (arr, index, newItem) => [
// part of the array before the specified index
...arr.slice(0, index),
// inserted item
newItem,
// part of the array after the specified index
...arr.slice(index)
]
const result = insert(items, 1, 10)
console.log(result)
// [1, 10, 2, 3, 4, 5]