JSFiddle - React, Tailwind, and code Playground
JavaScript
var textarea = "<div>(example)</div>\n<span>Other example</span>";
var findreplace = {"<" : "<", ">" : ">", "\n" : "<br/>"};
textarea = textarea.replace(new RegExp("(" + Object.keys(findreplace).map(function(i){return i.replace(/[.?*+^$[\]\\(){}|-]/g, "\\$&")}).join("|") + ")", "g"), function(s){ return findreplace[s]});
console.log( textarea );