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setMutationHandler

MutationObserver wrapper to wait for the specified CSS selector

Version vom 10.02.2017. Aktuellste Version

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/12228/174273/setMutationHandler.js 

/* EXAMPLE:

	setMutationHandler(document, '.container p.some-child', function(nodes) {
		// single node:
		nodes[0].remove();

		// or multiple nodes:
		nodes.forEach(node => node.style.display = 'none');

		// disconnect the observer, this is useful for one-time jobs
		return false;
	});

    // the observation target parameter may be omitted so "document" will be used by default:
    // setMutationHandler('#some-id', function(nodes) { ....... });
*/

// ==UserScript==
// @name          setMutationHandler
// @description   MutationObserver wrapper to wait for the specified CSS selector
// @namespace     wOxxOm.scripts
// @author        wOxxOm
// @grant         none
// @version       2.1.1
// ==/UserScript==

function setMutationHandler(baseNode, selector, cb, options) {
	if (typeof baseNode == 'string') {
		options = cb;
		cb = selector;
		selector = baseNode;
		baseNode = document;
	}

	var ob;

	if (/^#[\w\d-]+$/.test(selector)) {
		selector = selector.substr(1);
		ob = new MutationObserver(MOhandlerForId);
	} else {
		ob = new MutationObserver(MOhandler);
	}

	ob.observe(baseNode || document, options || {subtree:true, childList:true});
	return ob;

	function MOhandler(mutations, observer) {
		if (mutations.length > 100 && !document.querySelector(selector))
			return;
		var found = [];
		for (var i=0, m; (m = mutations[i++]); ) {
			switch (m.type) {
				case 'childList':
					var nodes = m.addedNodes, nl = nodes.length;
					var textNodesOnly = true;
					for (var j=0; j < nl; j++) {
						var n = nodes[j];
						textNodesOnly &= n.nodeType == 3; // TEXT_NODE
						if (n.nodeType != 1) // ELEMENT_NODE
							continue;
						if (n.matches(selector))
							found.push(n);
						else if (n.querySelector(selector)) {
							n = n.querySelectorAll(selector);
							if (n.length < 1000)
								found.push.apply(found, n);
							else
								found = found.concat(found.slice.call(n));
						}
					}
					if (textNodesOnly && m.target.matches(selector))
						found.push(m.target);
					break;
				case 'attributes':
					if (m.target.matches(selector))
						found.push(m.target);
					break;
				case 'characterData':
					if (m.target.parentNode && m.target.parentNode.matches(selector))
						found.push(m.target.parentNode);
					break;
			}
		}
		if (!found.length)
			return;
		if (cb.call(ob, found) === false)
			ob.disconnect();
	}

	function MOhandlerForId(mutations, observer) {
		var el = document.getElementById(selector);
		if (!el || !baseNode.contains(el))
			return;
		if (cb.call(ob, [el]) === false)
			ob.disconnect();
	}
}