Conditional field in GraphQL Where query

Question

Using Apollo client I am trying to run a query that will return students with any status if the status field is empty. If there is a status filter it should be applied:

const statusWhere = inputs.status ? {  equals: $inputs.status  }: {};
query GetStudents($course: ID, $status: String, $statusWhere: status_bool_exp) {
    studentCourses (where :{
        status: {$statusWhere},
        course: {
            id: {
                equals: $course
                }
        },
        # other fields, etc

This is giving error:

GraphQLError: Syntax Error: Expected Name, found "$".

Could you provide any hints?

Answer 1

After a bunch of trial and error I was able to figure it out myself. Posting it here because it could be useful for someone else.

Using the regular JS string interpolation variables works here.

So you need to define the condition as a string literal:

const statusWhere = inputs.status ? 'equals: "'+ inputs.status +'"' : '';

Then the whole gpl string looks like this:

gql`
          query GetStudents($course: ID) {
            studentCourses (where :{
                status: {
                   ${statusWhere}
                },                      
                course: {
                id: {
                  equals: $course
                }
              },
             
            })
            # fields etc`

In this case you do not need to pass your string variable as a query param.