fix(service-worker): correctly handle relative base href (#37922)

In some cases, it is useful to use a relative base href in the app (e.g.
when an app has to be accessible on different URLs, such as on an
intranet and the internet - see #25055 for a related discussion).

Previously, the Angular ServiceWorker was not able to handle relative
base hrefs (for example when building the with `--base-href=./`).

This commit fixes this by normalizing all URLs from the ServiceWorker
configuration wrt the ServiceWorker's scope.

Fixes #25055

PR Close #37922

packages/service-worker/config/src/generator.ts

@@ -131,7 +131,10 @@ function matches(file: string, patterns: {positive: boolean, regex: RegExp}[]):
 
 function urlToRegex(url: string, baseHref: string, literalQuestionMark?: boolean): string {
   if (!url.startsWith('/') && url.indexOf('://') === -1) {
-    url = joinUrls(baseHref, url);
+    // Prefix relative URLs with `baseHref`.
+    // Strip a leading `.` from a relative `baseHref` (e.g. `./foo/`), since it would result in an
+    // incorrect regex (matching a literal `.`).
+    url = joinUrls(baseHref.replace(/^\.(?=\/)/, ''), url);
   }
 
   return globToRegex(url, literalQuestionMark);