codex-team/editor.js

Memory leak in Shortcuts class

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#2631 aperta il 21 feb 2024

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Descrizione

Editor.js Version

v2.29.0

Issue description

Hi!

I've found a memory leak in the Shortcuts class. When you remove the shortcut for an element you don't check if the element's shortcuts are empty and left the element in the registeredShortcuts map (with an empty array):

https://github.com/codex-team/editor.js/blob/b619946e8f23ebc9ccfc41ef653439278e99491e/src/components/utils/shortcuts.ts#L89

If you create a new EditorJS and destroys it, you will see a bunch of detached elements referenced by registeredShortcuts map.

Steps to reproduce:

You can reproduce the issue with this simple html:

<html>
  <body>
    <button id="remove">Remove</button>
    <div id="editor" style="min-width: 700px"></div>
    <script src="https://cdn.jsdelivr.net/npm/@editorjs/editorjs@latest"></script>
    <script>
      let editor = new EditorJS({
        holder: 'editor',
      });

      function remove() {
        document.querySelector('#editor').remove();
        editor.isReady.then(() => {
          editor.destroy();
          editor = undefined;
        });
      }
      document.querySelector('#remove').addEventListener('click', remove);
    </script>
  </body>
</html>

Press "Remove" button and take a snapshot in Chrome dev tools. You will see detached HTMLDivElement's referenced by registeredShortcuts:

screenshot

If you remove the element from the map when the shortcuts array is empty, the problem disappears:

const newShortcuts = shortcuts.filter(el => el !== shortcut);

newShortcuts.length===0?
  this.registeredShortcuts.delete(element):
  this.registeredShortcuts.set(element, newShortcuts);

screenshot2

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