How to use the default font size selector with custom Quill toolbar?

The normal/default Quill editor uses this kind of size editor:

I am building a custom toolbar using the tools provided by Quill. That looks like this:

        const toolbarOptions = [
            [
                { font: ['Lato,sans-serif'] },
            ],
            ['size'],
            ['bold', 'italic', 'underline'],
            ['link'],
            ['clean'],
        ];

If I alter the ‘size’ array to be [{ size: ['10px', '12px' ... }] etc, the dropdown ends up looking like this:

How can I use the default size that comes with the editor in a custom configuration of options?