GitHub Commit Compare Picker

Select commits on GitHub and compare them
换行
// ==UserScript==
// @name         GitHub Commit Compare Picker
// @namespace    github-commit-compare-picker
// @version      1.1.0
// @description  Select commits on GitHub and compare them
// @match        https://github.com/*
// @run-at       document-idle
// @grant        none
// @license MIT
// ==/UserScript==
console.log("GitHub compare userscript loaded");
(function () {
  "use strict";

  var CHECKBOX_CLASS = "gh-commit-compare-checkbox";
  var BUTTON_ID = "gh-commit-compare-button";

  function parsePage() {
    var match = location.pathname.match(
      /^\/([^/]+)\/([^/]+)\/commits(?:\/(.+?))?\/?$/
    );

    if (!match) {
      return null;
    }

    return {
      owner: match[1],
      repo: match[2],
      branch: match[3] ? decodeURIComponent(match[3]) : "HEAD"
    };
  }

  function getShaLinks(page) {
    var prefix =
      "/" +
      page.owner +
      "/" +
      page.repo +
      "/commit/";

    var links = Array.from(
      document.querySelectorAll(
        'a[href^="' + prefix + '"]'
      )
    );

    return links.filter(function (link) {
      var text = (link.innerText || "").trim();

      // We specifically want the visible short SHA link.
      return /^[0-9a-f]{7,40}$/i.test(text);
    });
  }

  function getSelected() {
    return Array.from(
      document.querySelectorAll(
        "." + CHECKBOX_CLASS + ":checked"
      )
    ).map(function (box) {
      return {
        sha: box.getAttribute("data-sha"),
        order: Number(box.getAttribute("data-order"))
      };
    });
  }

  function updateButton() {
    var button = document.getElementById(BUTTON_ID);
    var page = parsePage();

    if (!button || !page) {
      return;
    }

    var selected = getSelected();

    if (selected.length === 0) {
      button.innerText = "Diff";
      button.disabled = true;
      button.style.opacity = "0.5";
    } else if (selected.length === 1) {
      button.innerText = "Diff to " + page.branch;
      button.disabled = false;
      button.style.opacity = "1";
    } else {
      button.innerText = "Diff selected";
      button.disabled = false;
      button.style.opacity = "1";
    }
  }

  function installCheckboxes() {
    var page = parsePage();

    if (!page) {
      return;
    }

    var shaLinks = getShaLinks(page);

    shaLinks.forEach(function (shaLink, index) {
      var sha = (shaLink.innerText || "").trim();

      // Already installed?
      if (
        document.querySelector(
          "." +
            CHECKBOX_CLASS +
            '[data-sha="' +
            sha +
            '"]'
        )
      ) {
        return;
      }

      var box = document.createElement("input");

      box.type = "checkbox";
      box.className = CHECKBOX_CLASS;
      box.setAttribute("data-sha", sha);
      box.setAttribute("data-order", String(index));

      box.style.width = "14px";
      box.style.height = "14px";
      box.style.margin = "0 6px";
      box.style.padding = "0";
      box.style.flex = "0 0 auto";
      box.style.alignSelf = "center";
      box.style.verticalAlign = "middle";
      box.style.cursor = "pointer";

      box.addEventListener("change", function () {
        if (getSelected().length > 2) {
          box.checked = false;
        }

        updateButton();
      });

      /*
       * GitHub currently looks approximately like:
       *
       * SHA link
       * <div>copy button</div>
       *
       * Put checkbox between them.
       */
      var next = shaLink.nextElementSibling;

      if (
        next &&
        next.querySelector &&
        next.querySelector("svg.octicon-copy")
      ) {
        shaLink.parentNode.insertBefore(box, next);
      } else {
        shaLink.parentNode.insertBefore(
          box,
          shaLink.nextSibling
        );
      }
    });

    /*
     * Recalculate order based on actual DOM position.
     * GitHub displays newest first.
     */
    var boxes = Array.from(
      document.querySelectorAll("." + CHECKBOX_CLASS)
    );

    boxes.forEach(function (box, index) {
      box.setAttribute("data-order", String(index));
    });
  }

  function installButton() {
    if (document.getElementById(BUTTON_ID)) {
      return;
    }

    var button = document.createElement("button");

    button.id = BUTTON_ID;
    button.type = "button";
    button.innerText = "Diff";
    button.disabled = true;

    button.style.position = "fixed";
    button.style.right = "28px";
    button.style.bottom = "28px";
    button.style.zIndex = "999999";

    button.style.padding = "8px 16px";
    button.style.border =
      "1px solid rgba(31, 35, 40, 0.15)";
    button.style.borderRadius = "6px";

    button.style.background = "#1f883d";
    button.style.color = "white";
    button.style.fontWeight = "600";
    button.style.fontSize = "14px";

    button.style.boxShadow =
      "0 3px 12px rgba(0,0,0,0.20)";

    button.style.cursor = "pointer";
    button.style.opacity = "0.5";

    button.addEventListener("click", function () {
      var page = parsePage();

      if (!page) {
        return;
      }

      var selected = getSelected();

      if (selected.length === 0) {
        return;
      }

      var oldRef;
      var newRef;

      if (selected.length === 1) {
        oldRef = selected[0].sha;
        newRef = page.branch;
      } else {
        selected.sort(function (a, b) {
          return a.order - b.order;
        });

        // GitHub list: newest first.
        newRef = selected[0].sha;
        oldRef = selected[1].sha;
      }

      var url =
        "https://github.com/" +
        page.owner +
        "/" +
        page.repo +
        "/compare/" +
        encodeURIComponent(oldRef) +
        "..." +
        encodeURIComponent(newRef);

      window.location.href = url;
    });

    document.body.appendChild(button);

    updateButton();
  }

  function init() {
    if (!parsePage()) {
      return;
    }

    installButton();
    installCheckboxes();
    updateButton();
  }

  /*
   * GitHub renders commit rows asynchronously.
   *
   * Polling here is intentional. It is simple and robust,
   * and the work performed each time is tiny.
   */
  setInterval(function () {
    init();
  }, 500);

  /*
   * Also run immediately in case the page is already ready.
   */
  init();
})();