I am trying to add a select field and a title field to a certain block. I used this example as starting point:

Edited: My code is

const { assign } = lodash;
const { addFilter } = wp.hooks;
const { __ } = wp.i18n;

// Enable contenttype control on the following blocks
const enableBlockContentTypeAttribute = [
    'uagb/section',
];

// Available contenttype control options
const contenttypeControlOptions = [
    {
        label: __( 'None' ),
        value: '',
    },
    {
        label: __( 'Exercise' ),
        value: 'exercise',
    },
    {
        label: __( 'Workshop' ),
        value: 'workshop',
    },
    {
        label: __( 'Something' ),
        value: 'something',
    },
];

/**
 * Add contenttype control attribute to block.
 *
 * @param {object} settings Current block settings.
 * @param {string} name Name of block.
 *
 * @returns {object} Modified block settings.
 */
const addBlockContentTypeAttribute = ( settings, name ) => {
    // Do nothing if it's another block than our defined ones.

    if ( ! enableBlockContentTypeAttribute.includes( name ) ) {
        return settings;
    }

    settings.attributes = assign( settings.attributes, {
        contenttype: {
            type: 'string',
            default: contenttypeControlOptions[ 0 ].value,
        },
        contenttitle: {
            type: 'string',
            default: '',
        }

    } );

    return settings;
};

addFilter( 'blocks.registerBlockType', 'my-mods/attribute/contenttype', addBlockContentTypeAttribute );

const { createHigherOrderComponent } = wppose;
const { Fragment } = wp.element;
const { InspectorControls, InnerBlocks } = wp.editor;
const { PanelBody, PanelRow, SelectControl, TextControl } = wpponents;

/**
 * Create HOC to add content type control to inspector controls of block.
 */
const withContentTypeControl = createHigherOrderComponent( ( BlockEdit ) => {
    return ( props ) => {
    // Do nothing if it's another block than our defined ones.
    if ( ! enableBlockContentTypeAttribute.includes( props.name ) ) {
        return (
            <BlockEdit { ...props } />
        );
    }

    const { contenttype } = props.attributes;
    const { contenttitle } = props.attributes;

    function getContentTitle ( content ) {
        props.setAttributes({contenttitle: content});
    }

    return (
        <Fragment>
        <BlockEdit { ...props } />
            <InspectorControls>
    <PanelBody
    title={ __( 'Choose Content Type' ) }
    initialOpen={ true }
        >
        <SelectControl
    label={ __( 'Content Type' ) }
    value={ contenttype }
    options={ contenttypeControlOptions }
    onChange={ ( selectedSpacingOption ) => {
        props.setAttributes( {
            contenttype: selectedSpacingOption,
        } );
    } }
/>

<TextControl
    label={ __( 'Content Title' ) }
    value={ contenttitle }
    onChange={ ( getContentTitle ) => {
        props.setAttributes( {
            contenttitle: getContentTitle,
        });
    }}
/>

</PanelBody>
            </InspectorControls>
        </Fragment>
);
};
}, 'withSpacingControl' );

addFilter( 'editor.BlockEdit', 'my-mods/with-contenttype-control', withContentTypeControl );



// do something with these attributes - add header to section if exercise type block
const addContentTypeMarkup = ( element, blockType, attributes ) => {
    // Do nothing if it's another block than our defined ones.

    if ( ! enableBlockContentTypeAttribute.includes( blockType.name ) ) {
        return element;
    }
    if ( attributes.contenttitle) {

        // add header with anchor link and class name

        var title_slug = attributes.contenttitle.trim().split(/\s+/).join('-');
        const Heading = "h" + 3;
        return (
            <React.Fragment>
            <h3 id = {`${title_slug}`}>{attributes.contenttitle}</h3>
            {element}
            </React.Fragment>

    )
    } else {
        return element;
    }

};


addFilter( 'blocks.getSaveElement', 'my-mods/add-content-type-markup', addContentTypeMarkup);


import classnames from 'classnames';
function applyExtraClass( extraProps, blockType, attributes ) {
    if ( ! enableBlockContentTypeAttribute.includes( blockType.name ) ) {
        return extraProps;
    }
    const { contenttype } = attributes;


    //add class if content type set
    if ( contenttype !== '' ) {
        console.log('add class name for content type');
        extraProps.className = classnames( extraProps.className, 'sometopictype-'+contenttype );
    }
    return extraProps;
}

addFilter(
    'blocks.getSaveContent.extraProps',
    'my-mods/applyExtraClass',
    applyExtraClass
);

I am getting this error:

Invariant Violation: Minified React error #130; visit .html?invariant=130&args[]=undefined&args[]= for the full message or use the non-minified dev environment for full errors and additional helpful warnings.

When I go to the link I see

Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined.

Can't figure out what is causing this. Everything was working fine when I just had the select control. Then added the text control and it broke. Ideas? I am new to React so probably something I am not understanding about syntax or something.

Note: Now working with edited code.