JSFiddle - React, Tailwind, and code Playground

JavaScript

var array1 = new Array();

array1.push(1);
array1.push(2);


var array2 = new Array();

array2.push(3);
array2.push(4);

var array3 = new Array();
array3.push(array1);
array3.push(array2);
console.log(array3.length);
console.log(array3[0]);
console.log(array3[1]);