given a selector waits for elements to be inserted into the DOM and executes a callback for each match
As of
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/5679/122963/Wait%20For%20Elements.js
/**
* @param sel - the selector you want to wait for
* @param action - the callback that will be executed when element/s matching the given selector are found, it is passed the array of found elements
* @param stopLooking - if true the function will stop looking for more elements after the first match
*/
function waitForElems(sel, action, stopLooking) {
var tick;
var id = 'fke' + Math.floor(Math.random() * 12345);
var type = window.MutationObserver ? 'M' : 'S';
var lastMutation = Date.now();
var lastCall = Date.now();
var queuedCall;
function throttle(func) {
var now = Date.now();
clearTimeout(queuedCall);
// less than 100ms since last mutation
if(now - lastMutation < 100) {
// 500ms or more since last query
if(now - lastCall >= 500) {
func();
} else {
queuedCall = setTimeout(func, 100);
}
} else {
func();
}
lastMutation = now;
}
function findElem(sel) {
lastCall = Date.now();
var found = [].filter.call(document.querySelectorAll(sel), function(elem) {
return elem.dataset[id] !== 'y';
});
if(found.length > 0) {
if(stopLooking) {
type === 'M' ? tick.disconnect() : clearInterval(tick);
}
found.forEach(function(elem) {
elem.dataset[id] = 'y';
action(elem);
});
}
}
if(type === 'M') {
tick = new MutationObserver(throttle.bind(null, findElem.bind(null, sel)));
tick.observe(document.body, { subtree: true, childList: true });
} else {
tick = setInterval(findElem.bind(null, sel), 300);
}
findElem(sel);
return tick;
}
/**
* @param regex - should match the site you're waiting for
* @param action - the callback that will be executed when a matching url is visited
* @param stopLooking - if true the function will stop waiting for another url match after the first match
*/
function waitForUrl(regex, action, stopLooking) {
function checkUrl(urlTest) {
var url = window.location.href;
if(url !== lastUrl && urlTest(url)) {
if(stopLooking) {
clearInterval(tick);
}
lastUrl = url;
action();
}
lastUrl = url;
}
var urlTest = (typeof regex === 'function' ? regex : regex.test.bind(regex)),
tick = setInterval(checkUrl.bind(null, urlTest), 300),
lastUrl;
checkUrl(urlTest);
return tick;
}