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setMutationHandler

MutationObserver wrapper to wait for the specified CSS selector

As of 12. 10. 2015. See the latest version.

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/12228/79812/setMutationHandler.js 

/* EXAMPLE:
	
	setMutationHandler(document, '.container p.some-child', function(nodes) {
		// single node:
		nodes[0].remove();
		
		// or multiple nodes:
		nodes.forEach(function(node) {
			node.style.display = 'none';
		});

		//this.disconnect(); // disconnect the observer, this is useful for one-time jobs
		return true; // continue enumerating current batch of mutations
	});
*/

// ==UserScript==
// @name          setMutationHandler
// @description   MutationObserver wrapper to wait for the specified CSS selector
// @namespace     wOxxOm.scripts
// @author        wOxxOm
// @grant         none
// @version       2
// ==/UserScript==

function setMutationHandler(baseNode, selector, cb, options) {
	var ob = new MutationObserver(function(mutations) {
		for (var i=0, ml=mutations.length, m; (i<ml) && (m=mutations[i]); i++)
			for (var j=0, nodes=m.addedNodes, nl=nodes.length, n; (j<nl) && (n=nodes[j]); j++)
				if (n.nodeType == 1) 
					if ((n = n.matches(selector) ? [n] : n.querySelectorAll(selector)) && n.length)
						if (!cb.call(ob, Array.prototype.slice.call(n)))
							return;
	});
	ob.observe(baseNode, options || {subtree:true, childList:true}); 
	return ob;
}