Check if a TinyMCE editor is empty in WordPress

editorEmptyCheck.js

jQuery(document).ready(function ($) {

	// Check if TinyMCE is active
	if (typeof tinyMCE != "undefined") {
		$('form').on('submit', function () {
			// Get content of active editor
			var editorContent = tinyMCE.activeEditor.getContent();
			if ((editorContent === '' || editorContent === null)) {
				// Do stuff when TinyMCE is empty
			}
		});
	}

});