Can GraphQL add mutations have an optional latitude and longitude?

Users GraphQL
2

You are going to have to extract this out just a little bit, which may require some adjustments on your app using this mutation:

mutation addEvent(
  $title: String!
  $point: PointRef
) {
  addEvent(
    input: [{
      title: $title
      location: $point
    }]
  ) {
    id
    title
    location
  }
}

and then in your input type can be:

interface addEventInput {
  title: string
  point?: {
    latitude: number,
    longitude: number
  }
}