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setMutationHandler

MutationObserver wrapper to wait for the specified CSS selector

As of 2016-07-20. 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.greatest.deepsurf.us/scripts/12228/137072/setMutationHandler.js 

  1. /* EXAMPLE:
  2. 	
  3. 	setMutationHandler(document, '.container p.some-child', function(nodes) {
  4. 		// single node:
  5. 		nodes[0].remove();
  6. 		
  7. 		// or multiple nodes:
  8. 		nodes.forEach(function(node) {
  9. 			node.style.display = 'none';
  10. 		});
  11.  
  12. 		//this.disconnect(); // disconnect the observer, this is useful for one-time jobs
  13. 		return true; // continue enumerating current batch of mutations
  14. 	});
  15. */
  16.  
  17. // ==UserScript==
  18. // @name          setMutationHandler
  19. // @description   MutationObserver wrapper to wait for the specified CSS selector
  20. // @namespace     wOxxOm.scripts
  21. // @author        wOxxOm
  22. // @grant         none
  23. // @version       2.0.6
  24. // ==/UserScript==
  25.  
  26. function setMutationHandler(baseNode, selector, cb, options) {
  27. 	var queue = [];
  28. 	var ob = new MutationObserver(function handler(mutations) {
  29. 		if (mutations && mutations.length > 100) {
  30. 			if (!queue.length)
  31. 				setTimeout(handler, 0);
  32. 			queue.push(mutations);
  33. 			return;
  34. 		}
  35. 		do {
  36. 			if (!mutations) {
  37. 				mutations = queue.shift();
  38. 				if (!mutations)
  39. 					return;
  40. 			}
  41.  
  42. 			for (var i=0, ml=mutations.length, m; (i<ml) && (m=mutations[i]); i++) {
  43. 				switch (m.type) {
  44. 					case 'childList':
  45. 						if (m.addedNodes[0] && m.addedNodes[0].nodeType == 3) { // TEXT_NODE
  46. 							if (m.target.matches(selector) && !cb.call(ob, [m.target], m))
  47. 								return;
  48. 							continue;
  49. 						}
  50. 						for (var j=0, nodes=m.addedNodes, nl=nodes.length, n; (j<nl) && (n=nodes[j]); j++)
  51. 							if (n.nodeType == 1) { // ELEMENT_NODE
  52. 								if (n.matches(selector))
  53. 									n = [n];
  54. 								else if (n.querySelector(selector))
  55. 									n = Array.prototype.slice.call(n.querySelectorAll(selector));
  56. 								else
  57. 									continue;
  58. 								if (!cb.call(ob, n, m))
  59. 									return;
  60. 							}
  61. 						break;
  62. 					case 'attributes':
  63. 						if (m.target.matches(selector) && !cb.call(ob, [m.target], m))
  64. 							return;
  65. 						break;
  66. 					case 'characterData':
  67. 						if (m.target.parentNode && m.target.parentNode.matches(selector) && !cb.call(ob, [m.target.parentNode], m))
  68. 							return;
  69. 						break;
  70. 				}
  71. 			}
  72. 			mutations = null;
  73. 		} while (queue.length);
  74. 	});
  75. 	ob.observe(baseNode, options || {subtree:true, childList:true});
  76. 	return ob;
  77. }