JSFiddle - React, Tailwind, and code Playground

JavaScript

var reparse = function (text) {
    //first replace all the quotes, then restore them in all [code] tags
    var res = text.split('"').join('"'),
        codes = res.match(/\[code\].*?\[\/code\]/gi);
    for (var m in codes) res = res.split(codes[m]).join(codes[m].split('"').join('"'));
    return res
}
document.getElementById("commentForm").addEventListener("submit", function () {
    document.getElementById("msg").value = reparse(document.getElementById("msg").value)
}, false)