Add a link to a GitHub repo's first commit
// ==UserScript==
// @name GitHub First Commit
// @description Add a link to a GitHub repo's first commit
// @author chocolateboy
// @copyright chocolateboy
// @namespace https://github.com/chocolateboy/userscripts
// @version 2.5.0
// @license GPL: http://www.gnu.org/copyleft/gpl.html
// @include https://github.com/
// @include https://github.com/*
// @require https://code.jquery.com/jquery-3.3.1.min.js
// @require https://cdn.rawgit.com/pie6k/jquery.initialize/16342abd3d411a20d35390f3e4c966ceb37ec43e/jquery.initialize.min.js
// @grant GM_log
// @inject-into content
// ==/UserScript==
// XXX note: the unused grant is a workaround for a Greasemonkey bug:
// https://github.com/greasemonkey/greasemonkey/issues/1614
const COMMIT_BAR = 'div.commit-tease.js-details-container'
const FIRST_COMMIT =
`<span id="first-commit">
| <a id="first-commit-link" style="cursor: pointer" class="message">First commit</a>
</span>`
// this function extracts the URL of the repo's first commit and navigates to it.
// it is based on code by several developers, a list of whom can be found here:
// https://github.com/FarhadG/init#contributors
//
// XXX it doesn't work on private repos. a way to do that can be found here,
// but it requires an authentication token:
// https://gist.github.com/simonewebdesign/a70f6c89ffd71e6ba4f7dcf7cc74ccf8
function openFirstCommit (user, repo) {
return fetch(`https://api.github.com/repos/${user}/${repo}/commits`)
// the `Link` header has additional URLs for paging.
// parse the original JSON for the case where no other pages exist
.then(res => Promise.all([res.headers.get('link'), res.json()]))
.then(([link, commits]) => {
if (link) {
// the link header contains two URLs and has the following
// format (wrapped for readability):
//
// <https://api.github.com/repositories/1234/commits?page=2>;
// rel="next",
// <https://api.github.com/repositories/1234/commits?page=9>;
// rel="last"
// extract the URL of the last page (commits are ordered in
// reverse chronological order, like the CLI, so the oldest
// commit is on the last page)
const lastPage = link.match(/^.+?<([^>]+)>;/)[1]
// fetch the last page of results
return fetch(lastPage).then(res => res.json())
}
// if there's no link, we know we're on the only page
return commits
})
// get the last commit and extract the target URL
.then(commits => commits[commits.length - 1].html_url)
// navigate there
.then(url => location.href = url)
}
// add the "First commit" link as the last child of the commit bar
function addLink () {
const $commitBar = $(this)
const [user, repo] = $('meta[name="octolytics-dimension-repository_network_root_nwo"]')
.attr('content')
.split('/')
// the "First commit" link already exists when navigating to a repo's
// homepage via the back button. however, resurrecting the link in this way
// causes its onclick event handler to be unregistered (XXX why?), so we
// still need to re-attach it
let $firstCommit = $commitBar.find('#first-commit')
if (!$firstCommit.length) {
$firstCommit = $(FIRST_COMMIT)
$commitBar.append($firstCommit)
}
const $link = $firstCommit.find('#first-commit-link')
$link.on('click', event => {
$link.text('Loading...')
openFirstCommit(user, repo)
return false
})
}
// the commit bar (div.commit-tease) is statically defined in the HTML
// for users who aren't logged in. for logged-in users, it's loaded dynamically
// via an <include-fragment> custom element:
//
// https://github.com/github/include-fragment-element
//
// jquery.initialize fires the callback immediately if the element already exists,
// so it handles both cases
$.initialize(COMMIT_BAR, addLink)