how to push one array into another array in javascript code example

Example 1: 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

Example 2: javascript push all elements of array to another array

var arrayA = [1, 2];
var arrayB = [3, 4];
var newArray = arrayA.concat(arrayB);

Example 3: push another array to array typescript

var arrayA = [1, 2];
var arrayB = [3, 4];
var newArray = arrayA.concat(arrayB);