// ==UserScript==
// @name        GitHub Update Fork
// @version     0.2.0
// @description A userscript that adds a link to update your fork
// @license     MIT
// @author      Rob Garrison
// @namespace   https://github.com/Mottie
// @include     https://github.com/*
// @run-at      document-idle
// @grant       none
// @icon        https://github.githubassets.com/pinned-octocat.svg
// ==/UserScript==
(() => {
"use strict";
function getUpstreamBranch(compareLink, info) {
// Look for "commit behind" or "commits behind"
if (compareLink && info && /commits?\sbehind/.test(info.textContent)) {
// forked from link text ":user/:repo"
const regexp = /behind\s*(.+:[-\w.]+)/;
// The match will include the sentence period because branch names may
// include a version number, e.g. "user:my-branch-v1.0"
const branch = (info.textContent.match(regexp) || [])[1];
return branch
? branch.substring(0, branch.length - 1)
: null;
}
return null;
}
function getUserBranch() {
// The branch selector may contain a truncated branch name, so use the url
const path = window.location.pathname;
const index = path.indexOf("/tree/");
return index > -1
? path.substring(index + 6, path.length)
: "master";
}
function addLink(compareLink, info) {
const branch = getUpstreamBranch(compareLink, info);
if (branch) {
const userBranch = getUserBranch();
const prLink = compareLink.previousElementSibling;
const link = prLink.cloneNode();
// https://github.com/<FORK>/<REPO>/compare/<BRANCH>...<SOURCE>:<BRANCH>
link.href = `${compareLink.href}/${userBranch}...${branch}`;
link.classList.add("ghuf-update-link");
link.appendChild($("svg", prLink).cloneNode(true));
link.appendChild(document.createTextNode(" Update fork"));
prLink.insertAdjacentElement("beforebegin", link);
}
}
function init() {
const compareLink = $("a[href*='pull/new'] + a[href$='/compare']");
const info = compareLink?.closest(".Box")?.firstElementChild;
if (compareLink && info) {
addLink(compareLink, info);
}
}
function $(str, el = document) {
return el.querySelector(str);
}
document.addEventListener("pjax:end", init);
init();
})();