JSFiddle - React, Tailwind, and code Playground

JavaScript

var a = [1,2];
a.first = 'Hello';
a.second = 'Вася Пупкин';
    
for (var i in a) {
    document.writeln(i + ' = ' + a[i] + '<br>');       
}

document.writeln('length = ' + a.length + '<br>');