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import { Plugin } from "$fresh/server.ts";
export interface Options {  prefetch?: 'all' | 'by-attribute'};
const prefetch = ({ prefetch = 'all' }: Options): Plugin => {  const main = `data:application/javascript,export default function (state) {    if (window.requestIdleCallback) {      // prefetched links set      const prefetched = new Set();
      // only prefetch relative links      const isRelativeUrl = (href) => typeof href === "string" && !/^http(s)?:\/\/|#/.test(href);
      const createPrefetchLink = (href) => {        console.log('Prefetchig', href);        const linkTag = document.createElement('link');        linkTag.rel = 'prefetch';        linkTag.href = href;        linkTag.as = 'document';        document.head.appendChild(linkTag);      };        window.requestIdleCallback(() => {        document.querySelectorAll("${prefetch === 'all' ? "a" : "a[prefetch]"}").forEach((element) => {          const href = element.getAttribute("href");            if (isRelativeUrl(href) && prefetched.has(href) === false) {            prefetched.add(href);            createPrefetchLink(href);          }        })      });    }  }`
  return {    name: 'prefetch',    entrypoints: { main },    render: (ctx) => {      ctx.render()
      return {        scripts: [{ entrypoint: 'main', state: {} }]      }    }  }}
export default prefetch