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node-creation-observer

Callback binding for HTML Node creation events

Script này sẽ không được không được cài đặt trực tiếp. Nó là một thư viện cho các script khác để bao gồm các chỉ thị meta // @require https://update.greasyfork.org/scripts/19857/174436/node-creation-observer.js 

/**
 * https://github.com/soufianesakhi/node-creation-observer-js
 * MIT licensed
 * Copyright (c) 2016 Soufiane Sakhi
 */
var NodeCreationObserver = function () {
    var mutationObserver = null;
    var observedNodeAttribute = "observed";
    var listeners = {};
    var options = {
        childList: true,
        subtree: true
    };
    var ListenerContext = (function () {
        function ListenerContext(removeOnFirstMatch) {
            this.callbacks = [];
            this.removeOnFirstMatch = removeOnFirstMatch == undefined ? false : removeOnFirstMatch;
        }
        return ListenerContext;
    }());
    function onMutationCallback() {
        Object.keys(listeners).forEach(function (selector) {
            invokeCallbacks(selector);
        });
    }
    function invokeCallbacks(selector) {
        var callbacks = listeners[selector].callbacks;
        var elements = document.querySelectorAll(selector);
        var newElements = filterNewElements(elements);
        if (newElements.length > 0) {
            if (listeners[selector].removeOnFirstMatch) {
                removeListener(selector);
            }
            newElements.forEach(function (element) {
                callbacks.forEach(function (callback) {
                    callback.call(element, element);
                });
            });
        }
    }
    function filterNewElements(elements) {
        var newElements = [];
        for (var i = 0; i < elements.length; i++) {
            var element = elements[i];
            var attr = element.getAttribute(observedNodeAttribute);
            if (attr == null) {
                element.setAttribute(observedNodeAttribute, "1");
                newElements.push(element);
            }
        }
        ;
        return newElements;
    }
    function observe() {
        if (mutationObserver == null) {
            mutationObserver = new MutationObserver(onMutationCallback);
            mutationObserver.observe(document.documentElement, options);
        }
    }
    function removeListener(selector) {
        delete listeners[selector];
        if (Object.keys(listeners).length == 0) {
            stopObserving();
        }
    }
    function stopObserving() {
        if (mutationObserver != null) {
            mutationObserver.disconnect();
            mutationObserver = null;
        }
    }
    return {
        init: function (customObservedNodeAttribute) {
            observedNodeAttribute = customObservedNodeAttribute;
        },
        onCreation: function (selector, callback, removeOnFirstMatch) {
            if (!listeners[selector]) {
                listeners[selector] = new ListenerContext(removeOnFirstMatch);
            }
            listeners[selector].callbacks.push(callback);
            observe();
            if (document.querySelector(selector) != null) {
                invokeCallbacks(selector);
            }
        },
        remove: removeListener,
        stop: function () {
            listeners = {};
            stopObserving();
        }
    };
}();