Schema Appliances

Intro

---

Schema Appliances or 'schema extras' are parts of the GraphQL schema that is not a Node. This includes;

1. Enums
2. Scalars
3. Directives
4. Interfaces
5. Unions
6. Types
7. Schema Globals

Enums

---

You can use IdioEnum to apply Enumeration types to your GraphQL schema.

const StatusEnum = new IdioEnum({
    name: "StatusEnum",
    typeDefs: `
        enum StatusEnum {
            ONLINE
            OFFLINE
            INACTIVE
        }
    `,
    resolver: {
        ONLINE: "online",
        OFFLINE: "offline",
        INACTIVE: "inactive"
    }
});

const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User {
            name: String
            age: Int
            status: StatusEnum
        }

        ...
    `, 
    ...
});

const { typeDefs, resolvers } = combineNodes(
    [ User ], 
    { enums: [ StatusEnum ] }
)

You can encapsulate IdioEnums in a GraphQLNode.

const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User {
            name: String
            age: Int
            status: StatusEnum
        }

        ...
    `, 
    enums: [ StatusEnum ],
    ...
});

Scalars

---

You can use IdioScalar to apply Scalar types to your GraphQL schema. A scalar does not require typeDefs.

You can only specify scalars at combineNodes.

example uses graphql-type-json.

const JSONScalar = new IdioScalar({
    name: "JSON",
    resolver: GraphQLJSON
});

const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User {
            name: String
            age: Int
            metadata: JSON
        }

        ...
    `, 
    ...
});

const { typeDefs, resolvers } = combineNodes(
    [ User ], 
    { scalars: [ JSONScalar ] }
);

Directives

---

You can use IdioDirective to apply Directives to your GraphQL schema.

You can only specify directives at combineNodes.

example uses graphql-auth-directives.

const hasScopeDirective = new IdioDirective({
    name: "hasScope",
    typeDefs: `
        directive @hasScope(
            scopes: [ String ]!
        ) on FIELD_DEFINITION 
    `, 
    resolver: HasScopeDirective
});


const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User ...

        type Query {
            getUser: User @hasScope(scopes: [ "admin" ])
        }
    `, 
    ...
});

const { typeDefs, resolvers } = combineNodes(
    [ User ], 
    { directives: [ hasScopeDirective ] }
);

Interfaces

---

You can use IdioInterface to apply Interface types to your GraphQL schema.

const PersonInterface = new IdioInterface({
    name: "PersonInterface",
    typeDefs: `
    interface PersonInterface {
        eyeColor: String
        hairColor: String
    }`,
    resolver: {
        __resolveType(obj) {
            if (obj.name) {
                return "User";
            }
        }
    }
});


const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User implements PersonInterface {
            eyeColor: String
            hairColor: String
            name: String
            age: Int
        }

        type Query {
            getUser: PersonInterface
        }
    `, 
    ...
});

const { typeDefs, resolvers } = combineNodes(
    [ User ], 
    { interfaces: [ PersonInterface ] }
);

You can encapsulate IdioInterfaces in a GraphQLNode.

const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User {
            name: String
            age: Int
            status: StatusEnum
        }

        ...
    `, 
    interfaces: [ PersonInterface ],
    ...
});

Unions

---

You can use IdioUnion to apply Union types to your GraphQL schema.

const UserUnion = new IdioUnion({
    name: "UserUnion",
    typeDefs: `union UserUnion = User | Admin`,
    resolver: {
        __resolveType(obj) {
            if (obj.admin) {
                return "Admin";
            }
        }
    }
});


const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User ...

        type Query {
            getUser: UserUnion
        }
    `, 
    ...
});

const { typeDefs, resolvers } = combineNodes(
    [ User ], 
    { 
        unions: [ UserUnion ],
        schemaGlobals: `
            type Admin {
                name: String
                age: Int
                roles: [ String ]
            }
        `
    }
);

You can encapsulate IdioUnions in a GraphQLNode.

const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User {
            name: String
            age: Int
            status: StatusEnum
        }

        ...
    `, 
    unions: [ UserUnion ],
    ...
});

Types

---

You can use GraphQLType to apply Object Types to your GraphQL schema.

const Metadata = new GraphQLType({
    name: "Metadata",
    typeDefs: `
        type Metadata {
            lastLogin: String
        }
    `,
    resolvers: {
        lastLogin: () => { ... }
    }
});


const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User {
            metadata: Metadata
        }

        type Query ...
    `, 
    ...
});

const { typeDefs, resolvers } = combineNodes(
    [ User ], 
    { 
        types: [ Metadata ]
    }
);

You can encapsulate GraphQLTypes in a GraphQLNode.

const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User {
            metadata: Metadata
        }

        ...
    `, 
    types: [ Metadata ],
    ...
});

Schema Globals

---

If you have type definition's that are generic to multiple Node's, you can provide a string or an array of strings to combineNodes where they will be injected into the resulting typeDefs.

If your Schema Global requires a resolver, you should prefer creating a GraphQLNode.

const User = new GraphQLNode({
    name: "User",
    typeDefs: `
        type User {
            name: String
            age: Int
            timeStamp: TimeStamp
        }

        ...
    `, 
    ...
});

const { typeDefs, resolvers } = await combineNodes(
    [ User ], 
    { 
        schemaGlobals: [ 
            `
            type TimeStamp {
                updatedAt: String
                createdAt: String
            }
            ` 
        ] 
    }
);