tampermonkey-gmail-bug-report.js

// ==UserScript==
// @name         Observe
// @namespace    http://gist.github.com/dting
// @version      0.1
// @description  Change non-link matches for /bug-\d+/ to a link
// @author       You
// @match        https://mail.google.com/mail/u/0/*
// ==/UserScript==

(function() {
    const MutationObserver = window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver;
    const term = /BUG-\d+/g;
    const replFn = function replFn(match) {
        const link = document.createElement('a');
        link.href = 'http://bugtracker.com/id/' + match;
        link.target = '_blank';
        link.innerHTML = match;
        return link;
    };
    const observerOptions = {
        attributes: false,
        childList: true,
        characterData: false,
        subtree: true,
    };

    const replaceKW = function replaceKW(text) {
        const matches = [];
        let match = term.exec(text.data);
        while (match) {
            matches.push(match);
            match = term.exec(text.data);
        }
        for (let i = matches.length - 1; i > -1; i--) {
            const matched = matches[i];
            text.splitText(matched.index);
            text.nextSibling.splitText(matched[0].length);
            text.parentNode.replaceChild(replFn(matched[0]), text.nextSibling);
        }
    };

    const replace = function replace(obs) {
        obs.disconnect();
        const a = [];
        const walk = document.createTreeWalker(document.body, NodeFilter.SHOW_TEXT, null, false);
        let node = walk.nextNode();
        while(node) {
            a.push(node);
            node = walk.nextNode();
        }
        a.forEach(replaceKW);
        obs.observe(document.body, observerOptions);
    };

    const debounce = function debounce(fn, delay) {
        let timer = null;
        return function (...args) {
            clearTimeout(timer);
            timer = setTimeout(() => fn(...args), delay);
        };
    };
    const debouncedReplace = debounce(replace, 200);

    const observer = new MutationObserver(mutations => {
        mutations.forEach(mutation => {
            if (mutation.type === 'childList') {
                debouncedReplace(observer);
            }
        });
    });

    observer.observe(document.body, observerOptions);
})();