add at location js array code example

Example 1: insert into array js

// for me lol... pls don't delete!
// use splice to insert element
// arr.splice(index, numItemsToDelete, item); 
var list = ["hello", "world"]; 
list.splice( 1, 0, "bye"); 
//result
["hello", "bye", "world"]

Example 2: how to append object in array javascript

var select =[2,5,8];
var filerdata=[];
for (var i = 0; i < select.length; i++) {
  filerdata.push(this.state.data.find((record) => record.id == select[i]));
}
//I have a data which is object,
//find method return me the filter data which are objects
//now with the push method I can make array of objects