how to push add number into a variable code example

Example 1: javascript append element to array

// initialize array
var arr = [
  "Hi",
  "Hello",
  "Bonjour"
];

// append new value to the array
arr.push("Hola");

console.log(arr);

Example 2: javascript append array to end of array

const new_array = old_array.concat([value1[, value2[, ...[, valueN]]]])