Files
427e7578-d7bf-49c8-aee9-2dd…/app.js
ako a76f00a08a feat: implement P2P polling app with Automerge sync
Core functionality using Automerge CRDT for real-time P2P sync:
- Creates or loads a shared document via URL hash
- Syncs over BroadcastChannel (local tabs) and WebSocket (wss://sync.automerge.org)
- Persists state to IndexedDB
- Add poll options with case-insensitive duplicate detection
- Toggle-vote per option, tracked per-document in localStorage
- Options sorted by vote count descending
- 2-minute countdown timer that disables voting on expiry
- Copy-to-clipboard for shareable URL

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-03-11 14:49:12 +01:00

215 lines
5.7 KiB
JavaScript

import {
Repo,
BroadcastChannelNetworkAdapter,
WebSocketClientAdapter,
IndexedDBStorageAdapter,
isValidAutomergeUrl,
} from "@automerge/vanillajs";
const REPO = new Repo({
network: [
new BroadcastChannelNetworkAdapter(),
new WebSocketClientAdapter("wss://sync.automerge.org"),
],
storage: new IndexedDBStorageAdapter(),
});
let HANDLE;
function getVotedKey(docUrl) {
return `p2p-poll-voted:${docUrl}`;
}
function getVotedOptions() {
const key = getVotedKey(document.location.hash);
return new Set(JSON.parse(localStorage.getItem(key) || "[]"));
}
function markVoted(opt) {
const key = getVotedKey(document.location.hash);
const voted = getVotedOptions();
voted.add(opt);
localStorage.setItem(key, JSON.stringify([...voted]));
}
function unmarkVoted(opt) {
const key = getVotedKey(document.location.hash);
const voted = getVotedOptions();
voted.delete(opt);
localStorage.setItem(key, JSON.stringify([...voted]));
}
const locationHash = document.location.hash.substring(1);
const statusEl = document.getElementById("status");
const optionsList = document.getElementById("options-list");
const optionInput = document.getElementById("option-input");
const addBtn = document.getElementById("add-btn");
const duplicateMsg = document.getElementById("duplicate-msg");
const copyBtn = document.getElementById("copy-btn");
const timerEl = document.getElementById("timer");
const startVotingBtn = document.getElementById("start-voting-btn");
if (isValidAutomergeUrl(locationHash)) {
statusEl.textContent = "Loading document…";
try {
HANDLE = await REPO.find(locationHash);
statusEl.textContent = "";
} catch (err) {
statusEl.textContent = "Could not load document. Starting a new one.";
HANDLE = REPO.create({ options: [], votes: {}, deadline: null });
document.location.hash = HANDLE.url;
}
} else {
HANDLE = REPO.create({ options: [], votes: {}, deadline: null });
document.location.hash = HANDLE.url;
}
HANDLE.on("change", ({ doc }) => render(doc));
const initialDoc = HANDLE.doc();
if (initialDoc) render(initialDoc);
let timerInterval = null;
function render(doc) {
renderOptions(doc);
renderTimer(doc);
}
function renderOptions(doc) {
const votes = doc.votes || {};
const deadline = doc.deadline ?? null;
const now = Date.now();
const votingClosed = deadline !== null && now >= deadline;
const votedOptions = getVotedOptions();
const sorted = [...(doc.options || [])].sort(
(a, b) => (votes[b] || 0) - (votes[a] || 0),
);
optionsList.innerHTML = "";
sorted.forEach((opt) => {
const count = votes[opt] || 0;
const alreadyVoted = votedOptions.has(opt);
const item = document.createElement("div");
item.className = "option-item";
const label = document.createElement("span");
label.className = "option-label";
label.textContent = opt;
const voteBtn = document.createElement("button");
voteBtn.className = alreadyVoted ? "vote-btn voted" : "vote-btn";
voteBtn.textContent = alreadyVoted ? `${count}` : `${count}`;
voteBtn.disabled = votingClosed;
if (votingClosed) voteBtn.title = "Voting is closed";
else if (alreadyVoted) voteBtn.title = "Click to remove your vote";
voteBtn.addEventListener("click", () => {
if (alreadyVoted) {
unmarkVoted(opt);
HANDLE.change((d) => {
if (!d.votes) d.votes = {};
d.votes[opt] = Math.max(0, (d.votes[opt] || 0) - 1);
});
} else {
markVoted(opt);
HANDLE.change((d) => {
if (!d.votes) d.votes = {};
d.votes[opt] = (d.votes[opt] || 0) + 1;
});
}
});
item.appendChild(label);
item.appendChild(voteBtn);
optionsList.appendChild(item);
});
}
function renderTimer(doc) {
const deadline = doc?.deadline ?? null;
const now = Date.now();
if (deadline === null) {
timerEl.textContent = "";
startVotingBtn.hidden = false;
return;
}
startVotingBtn.hidden = true;
if (now >= deadline) {
timerEl.textContent = "Voting closed.";
timerEl.className = "timer closed";
clearInterval(timerInterval);
timerInterval = null;
return;
}
const remaining = Math.ceil((deadline - now) / 1000);
const mins = Math.floor(remaining / 60);
const secs = remaining % 60;
timerEl.textContent = `Voting closes in ${mins}:${secs.toString().padStart(2, "0")}`;
timerEl.className = "timer active";
if (!timerInterval) {
timerInterval = setInterval(() => {
const d = HANDLE.doc();
if (!d) return;
renderTimer(d);
renderOptions(d);
if (Date.now() >= d.deadline) {
clearInterval(timerInterval);
timerInterval = null;
}
}, 1000);
}
}
startVotingBtn.addEventListener("click", () => {
HANDLE.change((d) => {
d.deadline = Date.now() + 2 * 60 * 1000;
});
});
addBtn.addEventListener("click", () => {
const value = optionInput.value.trim();
if (!value) return;
const doc = HANDLE.doc();
const valueLower = value.toLowerCase();
const isDuplicate = (doc?.options || []).some(
(opt) => opt.toLowerCase() === valueLower,
);
if (isDuplicate) {
duplicateMsg.textContent = `"${value}" is already in the list.`;
duplicateMsg.hidden = false;
return;
}
duplicateMsg.hidden = true;
HANDLE.change((d) => {
if (!d.options) d.options = [];
d.options.push(value);
});
optionInput.value = "";
});
optionInput.addEventListener("keydown", (e) => {
if (e.key === "Enter") addBtn.click();
});
optionInput.addEventListener("input", () => {
duplicateMsg.hidden = true;
});
copyBtn.addEventListener("click", () => {
navigator.clipboard.writeText(window.location.href).then(() => {
copyBtn.textContent = "Copied!";
setTimeout(() => (copyBtn.textContent = "Copy URL"), 1500);
});
});