On my case I use https://polyfill.io https://polyfill.io which is a great service returning only what the browser needs by user agent. Some example url I used:

On my case I use https://polyfill.io https://polyfill.io which is a great service returning only what the browser needs by user agent. Some example url I used: https://cdn.polyfill.io/v2/polyfill.js?features=Element,requestAnimationFrame,Number.parseFloat,es6,Promise,Array.prototype.map,Map,Set https://cdn.polyfill.io/v2/polyfill.js?features=Element,requ.... It avoids adding a lot of useless polyfills for up-to-date browsers.