Q:

Confusion with babel polyfills

I was learning how babel.js works and faced a bit of confusion on how babel polyfills work, that is, for example, if we add promise polyfill to babel then does that polyfill enables babel to actually convert promise into older version thanks to the polyfill added. I just cannot get how babel polyfills work

A:

Polyfill will override native function. Such as promise-polyfill will override window.Promise. So you can use promise = new Promise in IE

