Uncaught ReferenceError: ClassicEditor is not defined

I want to fix this error without using the package.

<script>
    ClassicEditor
        .create( document.querySelector( '#body' ), {
            cloudServices: {
                tokenUrl: 'https://your-token-url.com',
            }
        } )
        .then( editor => {
            console.log( editor );
        } )
        .catch( error => {
            console.error( error );
        } );
</script>