Default values for nested input objects

[eknkc]

Hi,

It seems that if a nested input object is not supplied, the default values are not applied either;

const SomeConfig = new GraphQLInputObjectType({
  name: "X",
  fields: {
    foo: { type: GraphQLInt, defaultValue: 0 }
  }
})

const Query = new GraphQLObjectType({
  name: "Query",
  fields: {
    someQuery: {
      type: GraphQLString,
      args: {
        bar: { type: SomeConfig, defaultValue: {} }
      },
      resolve(parent, args) {
       // if no bar is supplied and bar has no defaultvalue, args.bar is null, this is expected.
       // if bar arg has a defaultValue: {} as above
       // args.bar.foo is not populated, args becomes {}
      }
     }
  }  
});

How can I make sure that the entire nested argument graph is populated with their default values?

[leebyron]

Thanks for bringing this up! Currently this indirect default values isn't supported, so you would have to manually write { foo: 0 } as the default value for your bar argument. This is interesting and deserves more thought, so leaving this issue open.

[eknkc]

Thanks!

I thought about writing a "extractDefault" function to create the default parameter for entire input object. Gonna need to call "getFields" on the input type to reflect on the inner fields and default values but getFields does not seem to be documented. Is it an internal API or safe to use?

Ekin Koc

On 9 May 2016 at 21:09:41, Lee Byron ([email protected](mailto:[email protected])) wrote:

Thanks for bringing this up! Currently this indirect default values isn't supported, so you would have to manually write { foo: 0 } as the default value for your bar argument. This is interesting and deserves more thought, so leaving this issue open.

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[yaquawa]

any progress on this ?? it has been 2 years!

[IvanGoncharov]

Sorry for the delay.
graphql-js implemented according to the spec so this change should be first added there.
If someone wants to be champion for this proposal here is the description of workflow:
https://github.com/facebook/graphql/blob/master/CONTRIBUTING.md#rfc-contribution-stages

[Sytten]

The closing of this feels a bit weird, did someone manage to open an RFC for that?

[benjie]

It seems obvious to me that the defaultValue should be coerced to match the type in the same way that a supplied argument would at runtime (otherwise it breaks the type safety guarantees of GraphQL); however @IvanGoncharov is correct that this is not specified in the GraphQL Spec, so I have opened an RFC here:

graphql/graphql-spec#793

And added it to the next GraphQL WG:

https://github.com/graphql/graphql-wg/blob/master/agendas/2020-12-03.md#agenda

[benjie]

In the mean time; here's a JS file that reproduces this issue:

const {
  graphqlSync,
  printSchema,
  GraphQLSchema,
  GraphQLObjectType,
  GraphQLInputObjectType,
  GraphQLInt,
} = require("graphql");

const ExampleInputObject = new GraphQLInputObjectType({
  name: "ExampleInputObject",
  fields: {
    number: {
      type: GraphQLInt,
      defaultValue: 3,
    },
  },
});

const Query = new GraphQLObjectType({
  name: "Query",
  fields: {
    example: {
      args: {
        inputObject: {
          type: ExampleInputObject,
          defaultValue: {},
        },
      },
      type: GraphQLInt,
      resolve(source, args) {
        return args.inputObject.number;
      },
    },
  },
});

const schema = new GraphQLSchema({
  query: Query,
});

console.log(printSchema(schema));

// All three of these should be equivalent?
const source = /* GraphQL */ `
  query A {
    example
  }
  query B {
    example(inputObject: {})
  }
  query C {
    example(inputObject: { number: 3 })
  }
`;
const result1 = graphqlSync({ schema, source, operationName: "A" });
const result2 = graphqlSync({ schema, source, operationName: "B" });
const result3 = graphqlSync({ schema, source, operationName: "C" });

console.log(JSON.stringify(result1.data));
console.log(JSON.stringify(result2.data));
console.log(JSON.stringify(result3.data));

And you can fix it by changing line 28:

           type: ExampleInputObject,
-          defaultValue: {},
+          defaultValue: coerceInputValue({}, ExampleInputObject),

(also import coerceInputValue from graphql).