JSFiddle - React, Tailwind, and code Playground

HTML

<div id="testDiv">
</div>

JavaScript

function splitNChars(txt, num) {
    var result = [];
    for (var i = 0; i < txt.length; i += num) {
        result.push(txt.substr(i, num));
    }
    return result;
}

var test = splitNChars("foofaafoofaafoofaafoofaafoofaa", 3);
var div = document.getElementById("testDiv");
for (var i = 0; i < test.length; i++) {
    div.innerHTML += test[i] + "<br/>";
}