dwp-guten/dw-guten.js

( function( wp ) {
	
	var SupButton = function( props ) {
		return wp.element.createElement(
			wp.editor.RichTextToolbarButton, {
				icon: 'arrow-up',
				title: 'Sup',
				onClick: function() {
					props.onChange( wp.richText.toggleFormat(
						props.value,
						{ type: 'dw-guten/sup' }
					) );
				},
				isActive: props.isActive,
			}
		);
	}

	var SubButton = function( props ) {
		return wp.element.createElement(
			wp.editor.RichTextToolbarButton, {
				icon: 'arrow-down',
				title: 'Sub',
				onClick: function() {
					props.onChange( wp.richText.toggleFormat(
						props.value,
						{ type: 'dw-guten/sub' }
					) );
				},
				isActive: props.isActive,
			}
		);
	}

	wp.richText.registerFormatType(
		'dw-guten/sup', {
			title: 'Sup',
			tagName: 'sup',
			className: null,
			edit: SupButton
		}
	);

	wp.richText.registerFormatType(
		'dw-guten/sub', {
			title: 'Sub',
			tagName: 'sub',
			className: null,
			edit: SubButton
		}
	);

} )( window.wp );