Gato GraphQL logo
Extensions Reference
Extensions ReferenceConditional Field Manipulation

Conditional Field Manipulation

Addition of meta directives @if and @unless to the GraphQL schema, to conditionally execute a nested directive on the field.

@if

@if executes its nested directives only if a condition has value true.

In this query, users "Leo" and "Peter" get their names converted to upper case, since they are in the "special user" array, while "Martin" does not:

query {
  users {
    name
      @passOnwards(as: "userName")
      @applyField(
        name: "_inArray"
        arguments: {
          value: $userName
          array: ["Leo", "John", "Peter"]
        }
        passOnwardsAs: "isSpecialUser"
      )
      @if(
        condition: $isSpecialUser
      )
        @strUpperCase
  }
}

...producing:

{
  "data": {
    "users": [
      {
        "name": "LEO"
      },
      {
        "name": "Martin"
      },
      {
        "name": "PETER"
      }
    ]
  }
}

@unless

Similar to @if, but it executes the nested directives when the condition is false.

In this query, it is user "Martin" who gets the name converted to upper case, while the other ones do not:

query {
  users {
    name
      @passOnwards(as: "userName")
      @applyField(
        name: "_inArray"
        arguments: {
          value: $userName
          array: ["Leo", "John", "Peter"]
        }
        passOnwardsAs: "isSpecialUser"
      )
      @unless(
        condition: $isSpecialUser
      )
        @strUpperCase
  }
}

...producing:

{
  "data": {
    "users": [
      {
        "name": "Leo"
      },
      {
        "name": "MARTIN"
      },
      {
        "name": "Peter"
      }
    ]
  }
}