GitHub Pull Request Unstable Warner Tampermonkey Script

unstable-warner.js

// ==UserScript==
// @name         Unstable Warner
// @namespace    http://tampermonkey.net/
// @version      0.5
// @description  Warn before merging unstable pull requests on GitHub
// @author       Terence Tuhinanshu @rajadain
// @match        https://github.com/**/pull/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    const submitButton = '.btn-group-merge>button[type="submit"]';
    const cancelButton = '.commit-form-actions>.js-menu-container>button[type="button"]';

    let message = "No problems with this Pull Request.";

    const hasFixups = () => {
        message = "This Pull Request has FIXUP or WIP commits. Do you really want to merge this?";
        return [...document.querySelectorAll('.commit-message')]
                .filter(commit => commit.innerText.toLowerCase().indexOf('fixup') >= 0 ||
                                  commit.innerText.toLowerCase().indexOf('wip') >= 0)
                .length > 0;
    };

    const isUnstable = () => {
        message = "This Pull Request is UNSTABLE. Do you really want to merge this?";
        return document.querySelector('.branch-action.branch-action-state-unstable');
    };

    document
        .querySelector(submitButton)
        .addEventListener('click', event => {
            if ((hasFixups() || isUnstable()) && !confirm(message)) {
                event.preventDefault();
                document.querySelector(cancelButton).click();
            }
        });
})();