JSFiddle - React, Tailwind, and code Playground
HTML
<textarea rows=10 cols=100 id="fill_me"></textarea>
JavaScript
var text = "row1<br /><br />row2";
$('#fill_me').val(text.replace(/<br \/>/g, '\n'));
<textarea rows=10 cols=100 id="fill_me"></textarea>
var text = "row1<br /><br />row2";
$('#fill_me').val(text.replace(/<br \/>/g, '\n'));