export function createLinks(
urlResolver: UrlResolver,
html: string,
baseUrl: ResolvedUrl,
deps: Set<ResolvedUrl>,
absolute: boolean = false): string {
const ast = parse5.parse(html, {locationInfo: true});
const baseTag = dom5.query(ast, dom5.predicates.hasTagName('base'));
const baseTagHref = baseTag ? dom5.getAttribute(baseTag, 'href') : '';
// parse5 always produces a <head> element.
const head = dom5.query(ast, dom5.predicates.hasTagName('head'))!;
for (const dep of deps) {
let href;
if (absolute && !baseTagHref) {
href = absUrl(urlResolver.relative(dep));
} else {
href = urlResolver.relative(baseUrl, dep);
}
const link = dom5.constructors.element('link');
dom5.setAttribute(link, 'rel', 'prefetch');
dom5.setAttribute(link, 'href', href);
dom5.append(head, link);
}
dom5.removeFakeRootElements(ast);
return parse5.serialize(ast);
}
protected async *
_transformIter(files: AsyncIterable<File>): AsyncIterable<File> {
for await (const file of files) {
if (file.path !== this.filePath) {
yield file;
continue;
}
const contents = await getFileContents(file);
const parsed = parse5.parse(contents, {locationInfo: true});
const base = dom5.query(parsed, baseMatcher);
if (!base || dom5.getAttribute(base, 'href') === this.newHref) {
yield file;
continue;
}
dom5.setAttribute(base, 'href', this.newHref);
dom5.removeFakeRootElements(parsed);
const updatedFile = file.clone();
updatedFile.contents = Buffer.from(parse5.serialize(parsed), 'utf-8');
yield updatedFile;
}
}