JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdn.ckeditor.com/4.5.7/standard/ckeditor.js"></script>
<div id="editor1">
	<p id="123">Test</p>
</div>
<button id="button">Test</button>

JavaScript

CKEDITOR.replace( 'editor1', {
	allowedContent: true,
	on: {
		instanceReady: function( evt ) {
			console.log( evt );
			CKEDITOR.document.getById( 'button' ).on( 'click', function() {
			try {
				alert( evt.editor.editable().find( '#123' ).getText() );
			} catch ( e ) {
				console.log( e );
				alert( 'Error is thrown' );
			}
			} );
		}
	}
} );