Smallest way to load smoothscroll polyfills

load-scroll-polyfill.js

// Loading "smoothscroll-polyfill" & "smoothscroll-anchor-polyfill" + setting scroll-behavior to smooth in 247 bytes:
((d,s,u)=>{d.documentElement.setAttribute('style','scroll-behavior:smooth');let i=s=>{let e=d.createElement('script');e.src=s;d.head.append(e)};i(u+s+`-polyfill/dist/${s}.min.js`);i(u+s+'-anchor-polyfill')})(document,'smoothscroll','//unpkg.com/')

// Readable version:
((doc, name, cdn) => {
  // Set scroll-behavior, setAttribute so it works in browsers that don't recognize the property
  doc.documentElement.setAttribute('style', 'scroll-behavior: smooth;');
  // Function to insert scripts...
  const insertScript = url => {
    const scriptElement = doc.createElement('script');
    scriptElement.src = url;
    doc.head.append(scriptElement);
  }
  // Insert both polyfills
  insertScript(`${ cdn }${ name }-polyfill/dist/${ name }.min.js`);
  insertScript(`${ cdn }${ name }-anchor-polyfill`);
})(document, 'smoothscroll', 'https://unpkg.com/')

// ES5 (262 bytes):
!function(d,s,u){d.documentElement.setAttribute('style','scroll-behavior:smooth');function i(s){var e=d.createElement('script');e.src=s;d.head.appendChild(e)};i(u+s+'-polyfill/dist/'+s+'.min.js');i(u+s+'-anchor-polyfill')}(document,'smoothscroll','//unpkg.com/')

// If we can live with the unminified version of "smoothscroll-polyfill" we can get down to 230 bytes:
((d,s,u)=>{d.documentElement.setAttribute('style','scroll-behavior:smooth');let i=s=>{let e=d.createElement('script');e.src=s;d.head.append(e)};i(u+s+'-polyfill');i(u+s+'-anchor-polyfill')})(document,'smoothscroll','//unpkg.com/')
// ...but now we saved 17 bytes just to load a huge unminified polyfill and ruin the savings :D