(Dumb question) Looping through array doesn’t work as desired in JavaScript [duplicate]

I have a really dumb question. Why does my code not work?

let Categories = ('City', 'Country', 'River', 'Name');

let i = 0;

while (i < Categories.length) {

It just prints out this:

so the different letters of the fourth index. Why? I already tried using for loops but I’m a beginner to JavaScript and Lua is really different…