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node-creation-observer

Callback binding for HTML Node creation events

Dieses Skript sollte nicht direkt installiert werden. Es handelt sich hier um eine Bibliothek für andere Skripte, welche über folgenden Befehl in den Metadaten eines Skriptes eingebunden wird // @require https://updategreasyfork.deno.dev/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();
        }
    };
}();