fix(GitHubDownloads): type error on latest with pre-downloads (#4030)

services/github/github-downloads.service.js

@@ -191,6 +191,11 @@ module.exports = class GithubDownloads extends GithubAuthV3Service {
         options: { qs: { per_page: 1 } },
         errorMessages: errorMessagesFor('repo not found'),
       })
+      // Note that the API will return an empty array if there are no releases
+      // https://github.com/badges/shields/issues/3786
+      if (!latestReleaseIncludingPrereleases) {
+        throw new NotFound({ prettyMessage: 'no releases' })
+      }
       releases = [latestReleaseIncludingPrereleases]
     } else if (tag) {
       const wantedRelease = await this._requestJson({

services/github/github-downloads.tester.js

@@ -32,6 +32,11 @@ t.create('downloads-pre for latest release')
   .get('/downloads-pre/photonstorm/phaser/latest/total.json')
   .expectBadge({ label: 'downloads@latest', message: isMetric })
 
+// https://github.com/badges/shields/issues/3786
+t.create('downloads-pre for latest release (no-releases)')
+  .get('/downloads-pre/badges/shields/latest/total.json')
+  .expectBadge({ label: 'downloads', message: 'no releases' })
+
 t.create('downloads for release without slash')
   .get('/downloads/atom/atom/v0.190.0/total.json')
   .expectBadge({ label: 'downloads@v0.190.0', message: isMetric })