Web development with old browsers

Question

How a web developer deal with browsers which doesn't support last html5/ES6/css3 features nowadays? Does he or she build a lot of page versions with polyfill for each browser ? Or old browsers aren't taken in consideration ? Where is the limit?

Answer 1

Web developers use tools like Babel. It transpiles any modern JS (ES6, ES7 and etc) to ES5, which is supported by old browsers.

Answer 2

Are these (Babel/ Sucrase / swc / Bublé ) compilers

Answer 3

Hope people start moving to modern browser

Answer 4

Using javascript functions