I am using gatsby with wordpress to display events from the events calendar API of wordpress . I am using the plugin gatsby-source-tribe-events to access the allTribeEvents graphql field . The problem is that if I have no events posted on wordpress the field allTribeEvents is not created and then if I run my graphql query on gatsby I get

Cannot query field "allTribeEvents" on type "Query"

So my problem is how to check if the field exists in graphql and query conditionally based on it .

My code :

React component to display events :

export default function Events() {
 
const data  = useStaticQuery(graphql`
   query EventsQuery {
    allTribeEvents {
      ...
     }
    }`);

//then I return my component based on the data 
}

So the point is that if no posts exist "allTribeEvents" is not created in grapqhl and I get an error

CodePudding user response：

So my problem is how to check if the field exists in graphql and query conditionally based on it .

Short answer, you can't. Essentially because when you query something, you expect some result. The problem here is that because of the defined worfklow (WordPress -> Gatsby -> GraphQL node creation), the steps are broken.

The ideal solution in this cases, is to define a Custom GraphQL Schema Definition that will help you to tell Gatsby that the allTribeEvents can be null.

Another possible workaround (far less clean) is to create an empty tribe event (maybe with empty spaces or with some kind of defined field) and treat it in the front-end to avoid printing it (let's say you have an event named "-", if you find that field in the GraphQL query, filter it).