refined-github · sindresorhus · Oct 4, 2018 · Oct 3, 2018 · Oct 3, 2018 · Oct 3, 2018
diff --git a/source/features/add-branch-buttons.js b/source/features/add-branch-buttons.js
@@ -2,17 +2,10 @@ import {h} from 'dom-chef';
 import select from 'select-dom';
 import compareVersions from 'tiny-version-compare';
 import * as icons from '../libs/icons';
-import * as cache from '../libs/cache';
 import {appendBefore} from '../libs/utils';
 import {groupSiblings} from '../libs/group-buttons';
-import {getRepoURL, isRepoRoot, getOwnerAndRepo} from '../libs/page-detect';
-
-// This regex should match all of these combinations:
-// "This branch is even with master."
-// "This branch is 1 commit behind master."
-// "This branch is 1 commit ahead of master."
-// "This branch is 1 commit ahead, 27 commits behind master."
-const branchInfoRegex = /([^ ]+)\.$/;
+import getDefaultBranch from '../libs/get-default-branch';
+import {getRepoURL, isRepoRoot} from '../libs/page-detect';
 
 function getTagLink() {
 	const tags = select
@@ -45,46 +38,20 @@ function getTagLink() {
 	return link;
 }
 
-async function getDefaultBranchNameIfDifferent() {
-	const {ownerName, repoName} = getOwnerAndRepo();
-	const cacheKey = `default-branch:${ownerName}/${repoName}`;
-
-	// Return the cached name if it differs from the current one
-	const cachedName = await cache.get(cacheKey);
-	if (cachedName) {
-		const currentBranch = select('[data-hotkey="w"] span').textContent;
-		return cachedName === currentBranch ? false : cachedName;
-	}
-
-	// We can find the name in the infobar, available in folder views
-	const branchInfo = select('.branch-infobar');
-	if (!branchInfo) {
-		return;
-	}
-
-	// Parse the infobar
-	const [, branchName] = branchInfo.textContent.trim().match(branchInfoRegex) || [];
-	if (branchName) {
-		cache.set(cacheKey, branchName, 1);
-		return branchName;
-	}
-}
-
 async function getDefaultBranchLink() {
-	if (select.exists('.repohead h1 .octicon-repo-forked')) {
-		return; // It's a fork, no "default branch" info available #1132
-	}
+	const defaultBranch = await getDefaultBranch();
+	const currentBranch = select('[data-hotkey="w"] span').textContent;
 
-	const branchName = await getDefaultBranchNameIfDifferent();
-	if (!branchName) {
+	// Don't show the button if we’re already on the default branch
+	if (defaultBranch === currentBranch) {
 		return;
 	}
 
 	let url;
 	if (isRepoRoot()) {
 		url = `/${getRepoURL()}`;
 	} else {
-		const branchLink = select(`.select-menu-item[data-name='${branchName}']`);
+		const branchLink = select(`.select-menu-item[data-name='${defaultBranch}']`);
 		if (!branchLink) {
 			return;
 		}
@@ -98,7 +65,7 @@ async function getDefaultBranchLink() {
 			aria-label="Visit the default branch">
 			{icons.branch()}
 			{' '}
-			{branchName}
+			{defaultBranch}
 		</a>
 	);
 }

diff --git a/source/libs/cache.js b/source/libs/cache.js
@@ -1,11 +1,12 @@
-export default async function getSet(key, getter, expiration) {
+export async function getSet(key, getter, expiration) {
 	const cache = await get(key);
-	if (cache === undefined) {
-		const value = getter();
-		if (value !== undefined) {
-			await set(key, value, expiration);
-			return value;
-		}
+	if (cache !== undefined) {
+		return cache;
+	}
+	const value = await getter();
+	if (value !== undefined) {
+		await set(key, value, expiration);
+		return value;
 	}
 }
 
@@ -16,7 +17,7 @@ export async function get(key) {
 	});
 
 	// If it's not in the cache, it's best to return "undefined"
-	if (value === null) {
+	if (value === null || value === undefined) {
 		return undefined;
 	}
 	return value;
@@ -41,14 +42,17 @@ if (!browser.runtime.getBackground) {
 		if (code === 'get-cache') {
 			const [cached] = document.cookie.split('; ')
 				.filter(item => item.startsWith(key + '='));
-
 			if (cached) {
 				const [, value] = cached.split('=');
 				sendResponse(JSON.parse(value));
+				console.log('CACHE: found', key, value);
 			} else {
 				sendResponse();
+				console.log('CACHE: not found', key);
 			}
 		} else if (code === 'set-cache') {
+			console.log('CACHE: setting', key, value);
+
 			// Store as JSON to preserve data type
 			// otherwise Booleans and Numbers become strings
 			document.cookie = `${key}=${JSON.stringify(value)}; max-age=${expiration ? expiration * 3600 * 24 : ''}`;

diff --git a/source/libs/get-default-branch.js b/source/libs/get-default-branch.js
@@ -0,0 +1,41 @@
+import select from 'select-dom';
+import * as cache from './cache';
+import * as api from './api';
+import {getOwnerAndRepo} from './page-detect';
+
+// This regex should match all of these combinations:
+// "This branch is even with master."
+// "This branch is 1 commit behind master."
+// "This branch is 1 commit ahead of master."
+// "This branch is 1 commit ahead, 27 commits behind master."
+const branchInfoRegex = /([^ ]+)\.$/;
+
+function parseBranchFromDom() {
+	if (select.exists('.repohead h1 .octicon-repo-forked')) {
+		return; // It's a fork, no "default branch" info available #1132
+	}
+
+	// We can find the name in the infobar, available in folder views
+	const branchInfo = select('.branch-infobar');
+	if (!branchInfo) {
+		return;
+	}
+
+	// Parse the infobar
+	const [, branchName] = branchInfo.textContent.trim().match(branchInfoRegex) || [];
+	return branchName; // `string` or undefined
+}
+
+async function fetchFromApi(user, repo) {
+	const response = await api.v3(`repos/${user}/${repo}`);
+	if (response && response.default_branch) {
+		return response.default_branch;
+	}
+}
+
+export default function () {
+	const {ownerName, repoName} = getOwnerAndRepo();
+	return cache.getSet(`default-branch:${ownerName}/${repoName}`,
+		() => parseBranchFromDom() || fetchFromApi(ownerName, repoName)
+	);
+}