Can't update the content of ck editor of zendesk ticket in chrome extension - ckeditor

Question

I have a headache problem regarding the ck editor of zendesk ticket.
I am going to update the ck editor manually in chrome extension by using jQuery.
I can get the HTML value and class name and also add class name into this ck editor.
But when I change the content of this ck editor, it is never changed.
let editable_content = $("#editor-view").find("div[data-test-id='omnicomposer-rich-text-ckeditor']");
editable_content.html("<p>Test Ck Editor</p>");
editable_content.addClass("test-editor");
const editorValue = $("#editor-view").find("div[data-test-id='omnicomposer-rich-text-ckeditor']").html();
The class is added to this content successfully and the value of editorValue is "Test Ck Editor", but the content of ck editor doesn't changed.
zendesk.com/agent/ticket/1 is the URL that contains ck editor.
Please help me to fix this issue.
Thanks.

Answer 1

According to the CKEditor docs, you can get the CKEditor instance from a DOM element using the ckeditorInstance property.
If your HTML is like this:
<!-- The editable element in the editor's DOM structure. -->
<div class="... ck-editor__editable ..." contenteditable="true">
<!-- Editable content. --></div>
Then you can grab the CKEditor instance like this:
// A reference to the editor editable element in the DOM.
const domEditableElement = document.querySelector( '.ck-editor__editable' );
// Get the editor instance from the editable element.
const editorInstance = domEditableElement.ckeditorInstance;
// Use the editor instance API.
editorInstance.setData( '<p>Hello world!<p>' );

Answer 2

For ckEditor 5 (that is currently used by zendesk), all the changes need to be done via the model.
In order to access the model, you have the ckeditorInstance property on the domElement that contains it.
The ckeditorInstance appears only in a background script that is ran with the world as main.
chrome.scripting.executeScript({world: 'MAIN', ...otherOptions})
Once you are able to access the model, then it is as simple (or complex) as writing JS code to change the ckEditor contents.