Foldable-diffs.user.js

// ==UserScript==
// @name         Foldable diffs
// @namespace    http://tampermonkey.net/
// @version      0.4
// @description  Adds a fold button to file diffs, and folds deleted files by default
// @author       gigaherz
// @match        https://bitbucket.org/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    var makeFoldButton = function($el) {
        var div = $("<div class='aui-buttons'><button class='aui-button aui-button-light'>－</button></div>");
        var btn = div.find('button');
        var toggleFolding = function(){
            var diff=$el.find(".diff-content-container");
            diff.toggle();
            btn.text(diff.is(':visible') ? "－" : "＋");
        };
        btn.click(toggleFolding);

        div.insertBefore($el.find('.diff-actions.secondary > .bb-sbs-patch').prev());

        $el.find('.heading').click(toggleFolding).find('button').click(function(){return false;});

        if ($el.has('.diff-entry-lozenge.aui-lozenge-error').length > 0)
            toggleFolding();
    };

    var makeFoldable = function() {
        $('.diff-container').each(function(el) {
            makeFoldButton($(this));
        });
    };

    var observeDomAdd = function(target, callback) {

        var children = target.children;
        for (var i = 0; i < children.length; i++) {
            if (callback(children[i]) === false)
            {
                return;
            }
        }

        var observer = new WebKitMutationObserver(function(mutations) {
            mutations.forEach(function(mutation) {
                for(let i = 0; i < (mutation.addedNodes.length || []); i++)
                {
                    if (callback(mutation.addedNodes[i]) === false)
                    {
                        break;
                    }
                }
            });
        });

        observer.observe(target, {
            childList: true
        });
    };

    var observeTab = function(target, id) {
        observeDomAdd(target, function(node) {
            if (node.id === id) {
                makeFoldable();
                return false;
            }
        });
    };

    var cs = document.getElementById("changeset-diff");
    if (cs) {
        makeFoldable();
    } else {
        var diff = document.getElementById("compare-diff");
        if (diff) {
            observeDomAdd(diff, function(node) {
                if (node.id === "compare-diff-content") {
                    observeTab(node, 'changeset-diff');
                    return false;
                }
            });
        } else {
            var pr = document.getElementById("pr-tab-content");
            if (pr) {
                observeTab(pr, 'pullrequest-diff');
            }
        }
    }
})();