waitForKeyElements utility function

A utility function for userscripts that detects and handles AJAXed content.

Dieses Skript sollte nicht direkt installiert werden. Es handelt sich hier um eine Bibliothek für andere Skripte, welche über folgenden Befehl in den Metadaten eines Skriptes eingebunden wird // @require https://update.greatest.deepsurf.us/scripts/446257/1059316/waitForKeyElements%20utility%20function.js

// ==UserScript==
// @version 1.0.0
// @name waitForKeyElements utility function
// @description A utility function for userscripts that detects and handles AJAXed content.
// @namespace https://github.com/CoeJoder/waitForKeyElements.js
// @author CoeJoder
// @homepage https://github.com/CoeJoder/waitForKeyElements.js
// @source https://raw.githubusercontent.com/CoeJoder/waitForKeyElements.js/master/waitForKeyElements.js
// 
// ==/UserScript==

/**
 * A utility function for userscripts that detects and handles AJAXed content.
 *
 * Usage example:
 *
 *     function callback(domElement) {
 *         domElement.innerHTML = "This text inserted by waitForKeyElements().";
 *     }
 * 
 *     waitForKeyElements("div.comments", callback);
 *     // or
 *     waitForKeyElements(selectorFunction, callback);
 *
 * @param {(string|function)} selectorOrFunction - The selector string or function.
 * @param {function} callback - The callback function; takes a single DOM element as parameter.
 *                              If returns true, element will be processed again on subsequent iterations.
 * @param {boolean} [waitOnce=true] - Whether to stop after the first elements are found.
 * @param {number} [interval=300] - The time (ms) to wait between iterations.
 * @param {number} [maxIntervals=-1] - The max number of intervals to run (negative number for unlimited).
 */
function waitForKeyElements(selectorOrFunction, callback, waitOnce, interval, maxIntervals) {
	if (typeof waitOnce === "undefined") {
		waitOnce = true;
	}
	if (typeof interval === "undefined") {
		interval = 300;
	}
	if (typeof maxIntervals === "undefined") {
		maxIntervals = -1;
	}
	var targetNodes = (typeof selectorOrFunction === "function")
			? selectorOrFunction()
			: document.querySelectorAll(selectorOrFunction);

	var targetsFound = targetNodes && targetNodes.length > 0;
	if (targetsFound) {
		targetNodes.forEach(function(targetNode) {
			var attrAlreadyFound = "data-userscript-alreadyFound";
			var alreadyFound = targetNode.getAttribute(attrAlreadyFound) || false;
			if (!alreadyFound) {
				var cancelFound = callback(targetNode);
				if (cancelFound) {
					targetsFound = false;
				}
				else {
					targetNode.setAttribute(attrAlreadyFound, true);
				}
			}
		});
	}

	if (maxIntervals !== 0 && !(targetsFound && waitOnce)) {
		maxIntervals -= 1;
		setTimeout(function() {
			waitForKeyElements(selectorOrFunction, callback, waitOnce, interval, maxIntervals);
		}, interval);
	}
}