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setMutationHandler

MutationObserver wrapper to wait for the specified CSS selector

Verzia zo dňa 13.02.2017. Pozri najnovšiu verziu.

Tento skript by nemal byť nainštalovaný priamo. Je to knižnica pre ďalšie skripty, ktorú by mali používať cez meta príkaz // @require https://update.greatest.deepsurf.us/scripts/12228/174877/setMutationHandler.js 

/* EXAMPLE:

	setMutationHandler('.container p.some-child', nodes => {
		nodes.forEach(node => node.style.display = 'none');
		return false; // disconnect the observer, this is useful for one-time jobs
	});

	setMutationHandler({
		processExisting: true,
		selector: '.container p.some-child',
		handler: nodes => nodes.forEach(node => node.style.display = 'none')
	});

	setMutationHandler({
		selector: '.container p.some-child',
		processExisting: false,       // optional
		target: document,             // optional
		childList: true,              // optional
		subtree: true,                // optional
		attributes: false,            // optional
		attributeFilter: [],          // optional
		attributeOldValue: false,     // optional
		characterData: false,         // optional
		characterDataOldValue: false, // optional
		handler: nodes => {
			nodes.forEach(node => node.style.display = 'none');
			return false; // disconnect the observer, this is useful for one-time jobs
		},
	});
*/

// ==UserScript==
// @name          setMutationHandler
// @description   MutationObserver wrapper to wait for the specified CSS selector
// @namespace     wOxxOm.scripts
// @author        wOxxOm
// @grant         none
// @version       3.0.1
// ==/UserScript==

function setMutationHandler(target, selector, handler, options) {
// or    setMutationHandler(selector, handler, options) {
// or    setMutationHandler(options) {
	if (typeof arguments[0] == 'string') {
		options = arguments[2] || {};
		handler = arguments[1];
		selector = arguments[0];
		target = document;
	} else if (arguments.length == 1 && target && typeof target.handler == 'function') {
		options = arguments[0];
		handler = options.handler;
		selector = options.selector;
		target = options.target || document;
	} else if (!(target instanceof Node)) {
		throw 'Bad params for setMutationHandler.\n' +
			'A: [optional Node] target, [String] selector, [Function] handler, [optional Object] options\n' +
			'B: [Object] options\n' +
			'Options: target, selector, handler, processExisting, childList, attributes, characterData, subtree, attributeOldValue, characterDataOldValue, attributeFilter';
	}
	if (options.processExisting && target.querySelector(selector))
		handler.call(null, Array.prototype.slice.call(target.querySelectorAll(selector)));
	if (!options.attributes && !options.characterData && !options.childList && options.subtree === undefined)
		options.childList = options.subtree = true;

	var cb;
	if (/^#[\w\d-]+$/.test(selector)) {
		selector = selector.substr(1);
		cb = MOhandlerForId;
	} else {
		cb = MOhandler;
	}
	var observer = new MutationObserver(cb);
	observer.observe(target, options || {subtree:true, childList:true});
	return observer;

	function MOhandler(mutations) {
		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 (handler.call(observer, found) === false)
			observer.disconnect();
	}

	function MOhandlerForId(mutations) {
		var el = document.getElementById(selector);
		if (el && target.contains(el))
			if (handler.call(observer, [el]) === false)
				observer.disconnect();
	}
}