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One-line description of what this script does.
// ==UserScript==
// @name YOUR_SCRIPT_NAME
// @namespace https://greasyfork.org/users/your-id
// @version 0.1.0
// @description One-line description of what this script does.
// @author You
// @license MIT
// @match https://example.com/*
// @run-at document-idle
// @grant GM_getValue
// @grant GM_setValue
// @grant GM_addStyle
// ==/UserScript==
/**
* GreasyFork-friendly guidelines used here:
* - No obfuscation, no eval/new Function.
* - Minimal @grant and permissions.
* - Clear comments + predictable structure.
* - Safe DOM operations + mutation observer cleanup.
*/
(() => {
'use strict';
// -----------------------------
// Config / Feature flags
// -----------------------------
/** Toggle debug logs (default: false). */
const DEBUG = false;
/** Namespaced storage key prefix to avoid collisions with other scripts. */
const STORE_PREFIX = 'your_script_name:';
/** Simple logger wrapper to avoid noisy console. */
const log = (...args) => { if (DEBUG) console.log('[YOUR_SCRIPT_NAME]', ...args); };
// -----------------------------
// Utilities
// -----------------------------
/**
* Read value from Greasemonkey/Tampermonkey storage.
* @template T
* @param {string} key
* @param {T} fallback
* @returns {T}
*/
function getStore(key, fallback) {
try {
return /** @type {any} */ (GM_getValue(STORE_PREFIX + key, fallback));
} catch (e) {
log('GM_getValue failed:', e);
return fallback;
}
}
/**
* Save value to storage.
* @param {string} key
* @param {any} value
*/
function setStore(key, value) {
try {
GM_setValue(STORE_PREFIX + key, value);
} catch (e) {
log('GM_setValue failed:', e);
}
}
/**
* Wait for an element to appear, then resolve.
* Uses polling with timeout to stay simple & robust.
* @param {string} selector
* @param {{timeoutMs?: number, intervalMs?: number, root?: ParentNode}} [opts]
* @returns {Promise<Element>}
*/
function waitForSelector(selector, opts = {}) {
const {
timeoutMs = 10_000,
intervalMs = 200,
root = document
} = opts;
return new Promise((resolve, reject) => {
const start = Date.now();
const timer = setInterval(() => {
const el = root.querySelector(selector);
if (el) {
clearInterval(timer);
resolve(el);
return;
}
if (Date.now() - start > timeoutMs) {
clearInterval(timer);
reject(new Error(`Timeout waiting for selector: ${selector}`));
}
}, intervalMs);
});
}
/**
* Add CSS safely.
* @param {string} css
*/
function addCss(css) {
try {
GM_addStyle(css);
} catch {
// Fallback for environments without GM_addStyle
const style = document.createElement('style');
style.textContent = css;
document.head.appendChild(style);
}
}
// -----------------------------
// Core logic (replace with your own)
// -----------------------------
/**
* Perform one-time initialization.
* Put your main logic here.
*/
async function main() {
log('init');
// Example: inject styles
addCss(`
/* YOUR_SCRIPT_NAME styles */
.ysn-hidden { display: none !important; }
`);
// Example: wait for key element
// (Replace selectors with your real target)
try {
const target = await waitForSelector('body');
log('target ready:', target);
// Example: apply once
applyOnce();
// Example: observe DOM changes if the site is SPA
startObserver();
} catch (e) {
console.warn('[YOUR_SCRIPT_NAME] init failed:', e);
}
}
/**
* Apply changes once (idempotent).
* Make sure repeated calls won't duplicate UI or listeners.
*/
function applyOnce() {
// Idempotency guard example
const markerId = 'ysn-marker';
if (document.getElementById(markerId)) return;
const marker = document.createElement('div');
marker.id = markerId;
marker.style.display = 'none';
document.documentElement.appendChild(marker);
// TODO: Your actual one-time modifications
// - Hide elements
// - Add buttons
// - Patch text
log('applyOnce done');
}
/**
* Mutation observer handler (keep fast!).
* Avoid heavy querySelectorAll on every mutation.
* @param {MutationRecord[]} mutations
*/
function onMutation(mutations) {
// Example: cheap detection strategy
for (const m of mutations) {
if (m.type === 'childList' && (m.addedNodes?.length || m.removedNodes?.length)) {
// TODO: Your incremental updates
// Tip: only touch relevant nodes or re-run small idempotent function
// applyIncremental();
break;
}
}
}
/** Keep observer reference for cleanup. */
let observer = null;
/** Start observing SPA page updates. */
function startObserver() {
if (observer) return;
observer = new MutationObserver(onMutation);
observer.observe(document.documentElement, { childList: true, subtree: true });
log('observer started');
}
/** Stop observer if needed. */
function stopObserver() {
if (!observer) return;
observer.disconnect();
observer = null;
log('observer stopped');
}
// -----------------------------
// Boot
// -----------------------------
// If the site is heavy SPA, document-idle is usually safer.
// You can also gate by readyState.
if (document.readyState === 'loading') {
document.addEventListener('DOMContentLoaded', main, { once: true });
} else {
void main();
}
// Optional: cleanup when leaving page (rarely needed in userscripts)
window.addEventListener('beforeunload', () => {
stopObserver();
});
})();