JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr = [];
var now = +new Date();
for (var i = 0; i < 1000000; i++) {
    var _arr = 'Jan_Fev_Mar_Abr_Mai_Jun_Jul_Ago_Set_Out_Nov_Dez'.split('_');
    arr.push(_arr);
}
console.log(arr.length);
console.log('A', (+new Date()) - now);
console.log('-------------------------');

var arr = [];
var now = +new Date();
for (var i = 0; i < 1000000; i++) {
    var _arr = ['Jan','Fev','Mar','Abr','Mai','Jun','Jul','Ago','Set','Out','Nov','Dez'];
    arr.push(_arr);
}
console.log(arr.length);
console.log('B', (+new Date()) - now)