JSFiddle - React, Tailwind, and code Playground

JavaScript

var text = 'Some text content <a href="http://domain.com/image/img.jpg"><img src="http://domain.com/image/img.jpg"></a> additional content';

text = text.replace(/href="(?:[^'\/]*\/)*([^']+)"/g, 'href="https://newdomain.com/$1"');

console.log(text);