Show releases count in releases tab and persist it

Follow-up to https://github.com/sindresorhus/refined-github/pull/12#issuecomment-185583858

extension/content.js

@@ -4,6 +4,7 @@ const path = location.pathname;
 const ownerName = path.split('/')[1];
 const repoName = path.split('/')[2];
 const repoUrl = `${ownerName}/${repoName}`;
+const releasesCountCacheKey = `${repoUrl}-releases-count`;
 const isDashboard = () => location.pathname === '/' || /(^\/(dashboard))/.test(location.pathname) || /(^\/(orgs)\/)(\w|-)+\/(dashboard)/.test(location.pathname);
 const isRepo = () => /^\/[^/]+\/[^/]+/.test(location.pathname);
 const isRepoRoot = () => location.pathname.replace(/\/$/, '') === `/${repoUrl}` || (/\/tree\/$/.test(location.href) && $('.repository-meta-content').length);
@@ -132,16 +133,35 @@ function moveVotes() {
 	}
 }
 
+function appendReleasesCount(count) {
+	if (!count) {
+		return;
+	}
+
+	$('.reponav-releases').append(`<span class="counter">${count}</span>`);
+}
+
+function cacheReleasesCount() {
+	if (isRepoRoot()) {
+		const releasesCount = $('.numbers-summary a[href$="/releases"] .num').text().trim();
+		appendReleasesCount(releasesCount);
+		chrome.storage.local.set({[releasesCountCacheKey]: releasesCount});
+	} else {
+		chrome.storage.local.get(releasesCountCacheKey, items => {
+			appendReleasesCount(items[releasesCountCacheKey]);
+		});
+	}
+}
+
 function addReleasesTab() {
 	const $repoNav = $('.js-repo-nav');
 	let $releasesTab = $repoNav.children('[data-selected-links~="repo_releases"]');
 	const hasReleases = $releasesTab.length > 0;
 
 	if (!hasReleases) {
-
-		$releasesTab = $(`<a href="/${repoUrl}/releases" class="reponav-item" data-hotkey="g r" data-selected-links="repo_releases /${repoUrl}/releases">
+		$releasesTab = $(`<a href="/${repoUrl}/releases" class="reponav-item reponav-releases" data-hotkey="g r" data-selected-links="repo_releases /${repoUrl}/releases">
 			<svg class="octicon octicon-tag" height="16" version="1.1" viewBox="0 0 14 16" width="14"><path d="M6.73 2.73c-0.47-0.47-1.11-0.73-1.77-0.73H2.5C1.13 2 0 3.13 0 4.5v2.47c0 0.66 0.27 1.3 0.73 1.77l6.06 6.06c0.39 0.39 1.02 0.39 1.41 0l4.59-4.59c0.39-0.39 0.39-1.02 0-1.41L6.73 2.73zM1.38 8.09c-0.31-0.3-0.47-0.7-0.47-1.13V4.5c0-0.88 0.72-1.59 1.59-1.59h2.47c0.42 0 0.83 0.16 1.13 0.47l6.14 6.13-4.73 4.73L1.38 8.09z m0.63-4.09h2v2H2V4z"></path></svg>
-			Releases
+			<span>Releases</span>
 		</a>`);
 	}
 
@@ -154,6 +174,8 @@ function addReleasesTab() {
 
 	if (!hasReleases) {
 		$repoNav.append($releasesTab);
+
+		cacheReleasesCount();
 	}
 }
 

extension/manifest.json

@@ -6,7 +6,8 @@
 	"manifest_version": 2,
 	"minimum_chrome_version": "48",
 	"permissions": [
-		"https://github.com/*"
+		"https://github.com/*",
+		"storage"
 	],
 	"icons": {
 		"128": "icon.png"

package.json

@@ -9,7 +9,8 @@
     "esnext": true,
     "envs": [
       "browser",
-      "jquery"
+      "jquery",
+      "webextensions"
     ],
     "ignores": [
       "extension/vendor/**"