Monitor replies to your Hacker News posts
// ==UserScript==
// @name Hacker News Thread Replies Monitor
// @version 0.10
// @description Monitor replies to your Hacker News posts
// @license WTFPL
// @match https://news.ycombinator.com/*
// @icon https://news.ycombinator.com/favicon.ico
// @grant none
// @namespace http://tampermonkey.net/
// ==/UserScript==
(async function () {
"use strict";
function parseDoc(doc) {
const threads = new Map();
for (const el of doc.querySelectorAll(".athing.comtr")) {
const parentEl = [].find.call(el.querySelectorAll(".navs a"), (el) => el.textContent == "parent");
const id = parseInt(el.id, 10);
threads.set(id, {
id,
age: new Date(el.querySelector(".age").getAttribute("title")),
author: el.querySelector(".hnuser").textContent,
parentId: parentEl != null
? parseInt(parentEl
.getAttribute("href")
.replace(/^(item\?id=|#)/, ""), 10)
: null,
text: el.querySelector(".commtext"),
});
}
return threads;
}
async function fetchThreadsDoc(userId) {
return new DOMParser().parseFromString(await (await fetch(`https://news.ycombinator.com/threads?id=${userId}`)).text(), "text/html");
}
function gatherUserReplies(userId, threads) {
const replyIds = new Map();
for (const [_, comment] of threads) {
if (comment.parentId == null) {
continue;
}
const parentComment = threads.get(comment.parentId);
if (parentComment == null) {
continue;
}
if (parentComment.author != userId) {
continue;
}
if (!replyIds.has(parentComment.id)) {
replyIds.set(parentComment.id, new Set());
}
replyIds.get(parentComment.id).add(comment.id);
}
return replyIds;
}
const LOCAL_STORAGE_KEY = "hn-thread-monitor";
function loadUnreadState() {
const item = localStorage.getItem(LOCAL_STORAGE_KEY);
if (item == null) {
return new Map();
}
return new Map(JSON.parse(item).map(([id, childStates]) => [
id,
new Map(childStates),
]));
}
function saveUnreadState(state) {
localStorage.setItem(LOCAL_STORAGE_KEY, JSON.stringify(Array.from(state).map(([id, childStates]) => [
id,
Array.from(childStates),
])));
}
function updateUnreadState(unreadState, replies) {
for (const [id, childrenIds] of replies) {
const childUnreadState = unreadState.get(id);
// Everything is new!
if (childUnreadState == null) {
unreadState.set(id, new Map([...childrenIds].map((childId) => [childId, true])));
continue;
}
// Only some things are new, so let's copy them over.
for (const childId of childrenIds) {
if (!childUnreadState.has(childId)) {
childUnreadState.set(childId, true);
}
}
}
}
function markPostsRead(unreadState, posts) {
for (const [_, childUnreadState] of unreadState) {
for (const [childId, _] of childUnreadState) {
if (!posts.has(childId)) {
continue;
}
childUnreadState.set(childId, false);
}
}
}
function countUnread(unreadState) {
let n = 0;
for (const [_, childUnreadState] of unreadState) {
for (const [_, unread] of childUnreadState) {
if (!unread) {
continue;
}
++n;
}
}
return n;
}
function sleep(ms, abortSignal) {
return new Promise((resolve, reject) => {
const id = setTimeout(() => {
resolve();
}, ms);
if (abortSignal) {
abortSignal.addEventListener("abort", () => {
clearTimeout(id);
reject(abortSignal.reason);
});
}
});
}
class Monitor {
static SLEEP_INTERVAL_MS = 30 * 1000;
me;
document;
abortController;
el;
constructor(me, document) {
this.me = me;
this.document = document;
this.abortController = new AbortController();
this.el = document.createElement("span");
this.el.style.padding = "0 0.5em";
const linkEl = this.document.querySelector('a[href^="threads?id"]');
linkEl.appendChild(this.document.createTextNode(" "));
linkEl.appendChild(this.el);
this.updateEl(countUnread(loadUnreadState()));
}
async start() {
while (true) {
try {
await sleep(Monitor.SLEEP_INTERVAL_MS, this.abortController.signal);
}
catch (e) {
break;
}
try {
await this.updateOnce(false);
}
catch (e) { }
}
}
stop() {
this.abortController.abort();
this.abortController = new AbortController();
}
updateEl(count) {
this.el.innerText = count != null ? count.toString() : "?";
this.el.style.background =
count != null && count > 0 ? "#ffffaa" : "#828282";
}
async updateOnce(markRead) {
const unreadState = loadUnreadState();
const threads = parseDoc(await fetchThreadsDoc(this.me));
const replies = gatherUserReplies(this.me, threads);
updateUnreadState(unreadState, replies);
if (markRead) {
markPostsRead(unreadState, parseDoc(this.document));
}
saveUnreadState(unreadState);
this.updateEl(countUnread(unreadState));
}
}
const me = document.getElementById("me").textContent;
const monitor = new Monitor(me, document);
await monitor.updateOnce(true);
document.addEventListener("visibilitychange", async () => {
switch (document.visibilityState) {
case "visible": {
monitor.start();
break;
}
case "hidden": {
monitor.stop();
break;
}
}
});
monitor.start();
})();