JSFiddle - React, Tailwind, and code Playground
JavaScript
text = '[url=http://examp.le][linktext][/url]';
alert(text.replace(/\[url=([^\s\]]+)\s*\](.*(?=\[\/url\]))\[\/url\]/g, '<a href="$1">$2</a>'))
text = '[url=http://examp.le][linktext][/url]';
alert(text.replace(/\[url=([^\s\]]+)\s*\](.*(?=\[\/url\]))\[\/url\]/g, '<a href="$1">$2</a>'))