tampermonkey_github_PR_collapse_all.js

// ==UserScript==
// @name         GitHub PRs collapse all feature
// @namespace    http://tampermonkey.net/
// @version      1.2.3
// @description  try to take over the world!
// @author       You
// @include      https://github.com/LykkeCity/*/pull/*
// @grant        none
// @require      http://code.jquery.com/jquery-3.3.1.min.js#sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8
// @downloadURL  http://bit.ly/pr-collapse
// ==/UserScript==

(function() {
    'use strict';
    const buttonSelector = '.js-details-container > .file-header > .file-actions > button';
    const buttonSelectorNotOpen = '.js-details-container:not(.open) > .file-header > .file-actions > button';

    $(function() {
        $('body').append(
`<style>
  .btn-collapse-all {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: transparent;
    border: 1px grey solid;
    border-radius: 20px;
    color: #6a737d;
    opacity: 0.5;
    transition: background .5s;
    padding: 2px 10px;
  }
  .btn-collapse-all:hover {
    opacity: 1;
    color: #fff;
    background: #0366d6;
    border-color: #0366d6;
  }
  ${buttonSelector} {
    width: 150px;
    border: 1px lightgray solid;
    border-radius: 20px;
  }
</style>
<button class="btn-collapse-all tooltipped tooltipped-w" aria-label="Collapse all opened files">collapse all</button>`
        );

        $('.btn-collapse-all').on('click', function() {
            customBtnCollapseAll();
        });
        
        
    });

    function customBtnCollapseAll() {
        const buttons = $(buttonSelectorNotOpen);
        // .js-details-container.open > .file-header > .file-actions > button
        console.log('collapseAll length', buttons.length);
        buttons.trigger('click');
    }
})();