如何在GRAPHQL中设置默认值

Question

I wanna set a default value in the role property but I don´t know how to do it. The idea is that the role property is "BASIC" by default for all users. I´m using express.

Sorry for my english, I´m not native, this is the code:

 const UserType = new GraphQLObjectType({

name: "User",
description: "User type",
fields: () => ({
id: { type: GraphQLID },
username: { type: GraphQLString },
email: { type: GraphQLString },
displayName: { type: GraphQLString },
phone: { type: GraphQLString },
role: { type:  GraphQLString}

}
),

});

thank you!

Answer 1

This is already answered on https://stackoverflow.com/a/51567429/10310278

And official documentation https://graphql.org/graphql-js/type/#example-5

Please check these things out.

Answer 2

This is done with the defaultValue property. But this is not possible for the GraphQLObjectType as you show.

const UserType = new GraphQLObjectType({
  name: 'User',
  description: 'User type',
  fields: () => ({
    id: { type: GraphQLID },
    username: { type: GraphQLString, defaultValue: 'default string' },
  }),
});

Object literal may only specify known properties, and 'defaultValue' does not exist in type 'GraphQLFieldConfig<any, any, { [argName: string]: any; }>'

So GraphQLObjectType has no default Value property.

You need to solve this in a different place, not here. For example, when using data, if the value you want is empty, you can use default instead.

...
...
data.username ?? 'default string'
...
...

---

But where does this defaultValue property work? It works with GraphQLInputObjectType .

For example:

  const filter = new GraphQLInputObjectType({
    name: "Filter",
    fields: () => ({
      min: { type: new GraphQLNonNull(graphql.GraphQLInt) },
      max: { type: graphql.GraphQLBoolean, defaultValue: 100 },
    }),
  });

and we can use it like this:

  ...
  query: {
    products: {
      type: new GraphQLList(productTypes),
      args: { filter: { type: new GraphQLNonNull(filter) } }, // <-----
      resolve: allProducts,
    },
  },
  ...