Expand/Collapse button on Github PRs

github-pr-expand-collapse.user.js

// Add a button to Collapse or Expand comments in a GitHub PR.
//
// Install Tampermonkey and add this as a script

// ==UserScript==
// @name         Github PRs: Expand / Collapse Comments.
// @namespace    TBD
// @version      0.1
// @description  Add a button to expand or collapse comments in a GitHub PR.
// @author       Jason Boyle
// @match        https://github.com/*
// @grant        GM_addStyle
// ==/UserScript==

GM_addStyle(
    '.pr-expand-collapse-btn { margin: 0 0 0 6px; position: absolute; right: 10px; top: 4px; } ' +
    '.collapsed { display: none; }'
);

window.addEventListener('load', () => {
    initializeButtons();
});

function initializeButtons() {
    const comments = document.querySelectorAll('.file.js-comment-container');

    for (let comment of comments) {
        const actions = comment.querySelector('.file-header');
        const diffTable = comment.querySelector('.blob-wrapper');
        const reviewComments = comment.querySelector('.review-comments');
        const expandCollapseBtn = document.createElement('a');

        expandCollapseBtn.classList.add('pr-expand-collapse-btn', 'btn', 'btn-sm');
        expandCollapseBtn.innerHTML = 'Collapse';
        actions.appendChild(expandCollapseBtn);

        expandCollapseBtn.onclick = function() {
            if ('Collapse' === expandCollapseBtn.innerHTML) {
                expandCollapseBtn.innerHTML = 'Expand';
            } else {
                expandCollapseBtn.innerHTML = 'Collapse';
            }

            diffTable.classList.toggle('collapsed');
            reviewComments.classList.toggle('collapsed');
        };
    }
}