Node Mutation Hook Library

A wrapper around MutationObserver to hook into creation of elements (filtered on CSS selector) or removal of nodes.

Ten skrypt nie powinien być instalowany bezpośrednio. Jest to biblioteka dla innych skyptów do włączenia dyrektywą meta // @require https://update.greasyfork.org/scripts/565361/1757829/Node%20Mutation%20Hook%20Library.js

Zadaj pytanie, napisz recenzję, lub zgłoś ten skrypt.

Wrap lines

// ==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
  });
}