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// @ts-check
/** * Checks if the document has a style sheet that finished loading (successfully * or not). This is not intended to detect pending or in progress reloading. * It’s possible for the document to have multiple style sheets with the same * `href`; if any are loaded the CSS is considered loaded. * @param {string} href CSS URL that’s absolute or relative to the *   `document.baseURI`. * @returns {boolean} Is the CSS loaded. */export default function documentHasStyleSheet(href) {  if (typeof href !== "string") {    throw new TypeError("Argument 1 `href` must be a string.");  }
  /** CSS absolute URL. */  const url = new URL(href, document.baseURI).href;
  for (const cssStyleSheet of document.styleSheets) {    if (cssStyleSheet.href === url) {      // Note that reading the rules errors if the style sheet is cross-domain      // and it’s `link` element doesn’t have `crossorigin="anonymous"`.      // Apparently the rules can be read without error for unparsable CSS.      if (cssStyleSheet.cssRules.length) return true;      else {        // Possible reasons for no style sheet rules:        //        // 1. Loading isn’t done.        // 2. Network error.        // 3. Unparsable CSS.        // 4. Really it has none.        //        // Reason 1 can be identified if the CSS request started and the        // response hasn’t ended yet. Note that the CSS could be falsely        // considered not loaded if its performance resource timing data was        // cleared, e.g. because the entry limit was exceeded or via        // `performance.clearResourceTimings()`. It’s also assumed this data        // isn’t affected by browser private mode, etc.
        const entries = /** @type {Array<PerformanceResourceTiming>} */ (          performance.getEntriesByName(url, "resource")        );
        if (          entries.length &&          // Apparently `responseEnd` doesn’t just relate to a server response;          // it will be present if a network error ended the request.          entries[entries.length - 1].responseEnd        ) {          return true;        }      }    }  }
  return false;}