Sample CKEditor5 JQuery validation plugin

sample.html

<form id="my_form_id">
  <textarea id="textarea" name="textarea" rows="6"></textarea>
  <button type="submit">Submit</button>
</form>

script.js

$().ready(function() {
  var editorTextarea

  ClassicEditor.create( document.querySelector( '#textarea' ) )
  .then (editor => {
      editorTextarea = editor;
  })
  .catch( error => {
      console.error( error );
  } );

  $ .validator.addMethod ("ckminlength", function (value, element, params) {
      let content_length = editorTextarea.plugins.get( 'WordCount' );
      return this.optional(element) || content_length.characters > params;
  }, "Please enter {0} characters minimum.");

  $("#my_form_id").validate({
      ignore: [],
      rules: {
          textarea: {
              required: true,
              ckminlength: 10,
          },
      },
      messages: {
          textarea: {
              required: "Your personnal text in your language",
              ckminlength: "Your personnal text in your language"
          }
      },
      submitHandler: function(form) {
          // some other code
          // maybe disabling submit button
          // then:
          form.submit();
      }
  });
});