create-the-option-item.ts

function buildOptionItem(app: DialogflowApp, aString: string): Responses.OptionItem {
    // Provide a key which is unique to each option.
    // And synonyms that the user can say alternativly to the title
    return app.buildOptionItem(`KEY_${aString}`, aString)
        .setTitle(`Option ${aString}`)
        // Description and image are optional.
        .setDescription(`Description for ${aString}`)
        .setImage('https://example.com/image.jpg', 'An image')
}