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setMutationHandler

MutationObserver wrapper to wait for the specified CSS selector

当前为 2017-02-11 提交的版本，查看 最新版本。

此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.cn-greasyfork.org/scripts/12228/174471/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(node => node.style.display = 'none');
  9.  
  10. 		// disconnect the observer, this is useful for one-time jobs
  11. 		return false;
  12. 	});
  13.  
  14.     // the observation target parameter may be omitted so "document" will be used by default:
  15.     // setMutationHandler('#some-id', function(nodes) { ....... });
  16.  
  17.     // process existing elements and set a mutation handler for the future ones
  18.     processExistingAndSetMutationHandler('a', processLinks);
  19. */
  20.  
  21. // ==UserScript==
  22. // @name          setMutationHandler
  23. // @description   MutationObserver wrapper to wait for the specified CSS selector
  24. // @namespace     wOxxOm.scripts
  25. // @author        wOxxOm
  26. // @grant         none
  27. // @version       3.0.0
  28. // ==/UserScript==
  29.  
  30. function setMutationHandler(baseNode, selector, cb, options) {
  31. 	if (typeof baseNode == 'string') {
  32. 		options = cb;
  33. 		cb = selector;
  34. 		selector = baseNode;
  35. 		baseNode = document;
  36. 	}
  37.  
  38. 	var ob;
  39.  
  40. 	if (/^#[\w\d-]+$/.test(selector)) {
  41. 		selector = selector.substr(1);
  42. 		ob = new MutationObserver(MOhandlerForId);
  43. 	} else {
  44. 		ob = new MutationObserver(MOhandler);
  45. 	}
  46.  
  47. 	ob.observe(baseNode || document, options || {subtree:true, childList:true});
  48. 	return ob;
  49.  
  50. 	function MOhandler(mutations, observer) {
  51. 		if (mutations.length > 100 && !document.querySelector(selector))
  52. 			return;
  53. 		var found = [];
  54. 		for (var i=0, m; (m = mutations[i++]); ) {
  55. 			switch (m.type) {
  56. 				case 'childList':
  57. 					var nodes = m.addedNodes, nl = nodes.length;
  58. 					var textNodesOnly = true;
  59. 					for (var j=0; j < nl; j++) {
  60. 						var n = nodes[j];
  61. 						textNodesOnly &= n.nodeType == 3; // TEXT_NODE
  62. 						if (n.nodeType != 1) // ELEMENT_NODE
  63. 							continue;
  64. 						if (n.matches(selector))
  65. 							found.push(n);
  66. 						else if (n.querySelector(selector)) {
  67. 							n = n.querySelectorAll(selector);
  68. 							if (n.length < 1000)
  69. 								found.push.apply(found, n);
  70. 							else
  71. 								found = found.concat(found.slice.call(n));
  72. 						}
  73. 					}
  74. 					if (textNodesOnly && m.target.matches(selector))
  75. 						found.push(m.target);
  76. 					break;
  77. 				case 'attributes':
  78. 					if (m.target.matches(selector))
  79. 						found.push(m.target);
  80. 					break;
  81. 				case 'characterData':
  82. 					if (m.target.parentNode && m.target.parentNode.matches(selector))
  83. 						found.push(m.target.parentNode);
  84. 					break;
  85. 			}
  86. 		}
  87. 		if (!found.length)
  88. 			return;
  89. 		if (cb.call(ob, found) === false)
  90. 			ob.disconnect();
  91. 	}
  92.  
  93. 	function MOhandlerForId(mutations, observer) {
  94. 		var el = document.getElementById(selector);
  95. 		if (!el || !baseNode.contains(el))
  96. 			return;
  97. 		if (cb.call(ob, [el]) === false)
  98. 			ob.disconnect();
  99. 	}
  100. }
  101.  
  102. function processExistingAndSetMutationHandler(baseNode, selector, cb, options) {
  103. 	if (typeof baseNode == 'string') {
  104. 		options = cb;
  105. 		cb = selector;
  106. 		selector = baseNode;
  107. 		baseNode = document;
  108. 	}
  109. 	baseNode = baseNode || document;
  110. 	if (baseNode.querySelector(selector))
  111. 	    cb.call(null, Array.prototype.slice.call(baseNode.querySelectorAll(selector)));
  112.     setMutationHandler(baseNode, selector, cb, options);
  113. }