Adds controls for expanding and collapsing all files in github pull requests. Add this to greasemonkey / tampermonkey

file_expander.js

// ==UserScript==
// @name         Github File collapser
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       Micheal Wilkinson
// @match        https://github.com/*/*/pull/*/files*
// @grant        none
// ==/UserScript==

(function () {
    var classes = 'open Details--on';
    var file_count = parseInt(document.getElementById('files_tab_counter').innerHTML.trim());
    var collapse_all = function() {
        for(int_diff = 0; int_diff < file_count; int_diff++) {
            var element = document.getElementById("diff-" + int_diff);
            if (null !== element) {
                var elementClasses = element.className;
                elementClasses = elementClasses.replace(new RegExp('(?:^|\\s)' + classes + '(?:\\s|$)'), ' ');
                elementClasses += ' ' + classes;
                document.getElementById("diff-" + int_diff).className = elementClasses;
            } else {
                break;
            }
        }
    };

    var expand_all = function() {

        for(int_diff = 0; int_diff < file_count; int_diff++) {
            var element = document.getElementById("diff-" + int_diff);
            if (null !== element) {
                var elementClasses = element.className;
                elementClasses = elementClasses.replace(new RegExp('(?:^|\\s)' + classes + '(?:\\s|$)'), ' ');
                document.getElementById("diff-" + int_diff).className = elementClasses;
            } else {
                break;
            }
        }
        expanded = true;
    };


    var outer_div = document.createElement('div');
    var inner_div = document.createElement('div');
    var expand_link = document.createElement('a');
    var collapse_link = document.createElement('a');
    var tool_div = document.getElementsByClassName('float-right pr-review-tools')[0];

    outer_div.className = 'diffbar-item';
    inner_div.className = 'BtnGroup';
    expand_link.className = 'btn btn-sm btn-outline BtnGroup-item tooltipped tooltipped-s';
    collapse_link.className = 'btn btn-sm btn-outline BtnGroup-item tooltipped tooltipped-s';

    expand_link.setAttribute('id', 'expand_all_link');
    collapse_link.setAttribute('id', 'collapse_all_link');

    expand_link.setAttribute('aria-label', 'Expand all files');
    collapse_link.setAttribute('aria-label', 'Collapse all files');

    expand_link.appendChild(document.createTextNode('Expand all'));
    collapse_link.appendChild(document.createTextNode('Collapse all'));
    inner_div.appendChild(expand_link);
    inner_div.appendChild(collapse_link);
    outer_div.appendChild(inner_div);
    tool_div.insertBefore(outer_div, tool_div.firstChild);


    document.getElementById("expand_all_link").addEventListener("click", expand_all);
    document.getElementById("collapse_all_link").addEventListener("click", collapse_all);
})();