A wrapper around MutationObserver to hook into creation of elements (filtered on CSS selector) or removal of nodes.
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.greasyfork.org/scripts/565361/1757829/Node%20Mutation%20Hook%20Library.js
// ==UserScript==
// @name Node Mutation Hook Library
// @namespace https://greasyfork.org/users/1545341
// @version 3.0.0
// @license MIT
// @author abcenjoyer
// @description A wrapper around MutationObserver to hook into creation of elements (filtered on CSS selector) or removal of nodes.
// ==/UserScript==
// callbacks should return a truthy value when they want no more elements to be processed, and falsy value when they want to continue processing
function hookCreation(selector, callback, callbackOnExisting) {
const observerTarget = document.documentElement;
if (callbackOnExisting) {
for (const element of observerTarget.querySelectorAll(selector)) {
if (callback(element)) {
return;
}
}
}
const observer = new MutationObserver((mutations) => {
for (const record of mutations) {
for (const node of record.addedNodes) {
if (node.nodeType === Node.ELEMENT_NODE) {
if (node.matches(selector)) {
if (callback(node)) {
observer.disconnect();
return;
}
}
for (const element of node.querySelectorAll(selector)) {
if (callback(element)) {
observer.disconnect();
return;
}
}
}
}
}
});
observer.observe(observerTarget, {
childList: true,
subtree: true
});
}
function hookRemoval(targetNode, callback) {
const observer = new MutationObserver((mutations) => {
for (const record of mutations) {
for (const node of record.removedNodes) {
if (node.contains(targetNode)) {
observer.disconnect();
callback();
}
}
}
});
// observing the entire document is required because if targetNode is deleted because an ancestor node was, observing the parent won't work
observer.observe(document, {
childList: true,
subtree: true
});
}