how to append an array in js code example

Example 1: append array js

var colors= ["red","blue"];
	colors.push("yellow"); //["red","blue","yellow"]

Example 2: javascript append array to array

const array1 = ['a', 'b', 'c'];
const array2 = ['d', 'e', 'f'];
const array3 = array1.concat(array2);

Example 3: 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