Creating Nodes

Intro

---

A "Node" GraphQLNode is designed to encapsulate a ObjectTypeDefinition together with its related resolvers & properties. Lets create a User Node.

const User = new GraphQLNode({
    name: "User"
});

TypeDefs

---

Here is the Schema Definition Language (SDL) for our Node.

type User {
    name: String
    age: Int
}

type Query {
    getUser: User
}

SDL can be referred to as typeDefs.

You can use filePaths, strings & even an AST when specifying typeDefs.

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

        type Query {
            getUser: User
        }
    `
});

Resolvers

---

A Node allows you to specify the following resolvers;

1. Query
2. Mutation
3. Subscription
4. Fields

Let's implement the getUser resolver...

Query

Mutation

Fields

Subscription

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

        type Query {
            getUser: User
        }
    `,
    resolvers: {
        Query: {
            getUser: (root, args, ctx) => { ... }
        }
    }
});

{
    typeDefs: `
        type User ...

        type Mutation {
            likeUser: User
        }
    `,
    resolvers: {
        Mutation: {
           likeUser: (root, args, ctx) => { ... }
        }
    }
}

{
    typeDefs: `
        type User {
            name: String
            posts: [Post]
        }

        ...
    `,
    resolvers: {
        Fields: {
            posts: (root, args, ctx) => { ... }
        }
    }
}

Subscriptions must return a 'subscribe' property that resolves to an async iterator!

{
    typeDefs: `
        type User ...

        type Subscription {
            userUpdate: User
        }
    `,
    resolvers: {
        Subscription: {
            userUpdate: {
                subscribe: (root, args, ctx) => asyncIterator()
            }
        }
    }
}

Injections

---

It's recommended to inject dependencies into your Node, this helps with testing. For each resolver injections will be a property on the context parameter.

new GraphQLNode({
    injections: { ... }
})

const User = new GraphQLNode({
    name: "User",
    typeDefs: "./User.gql",
    injections: {
        UserModel
    },
    resolvers: {
        Query: {
            getUser: (root, args, context) => {
                return context.injections.UserModel.findOne()
            }
        }
    }
});

Nodes

---

You can recursively nest nodes to reflect domains & work with architectural constraints.

const Comment = new GraphQLNode({
    name: "Comment",
    ...
});

const Post = new GraphQLNode({
    name: "Post",
    nodes: [ Comment ],
    ...
});

const User = new GraphQLNode({
    name: "User",
    nodes: [ Post ]
    ...
});

Enums

---

You can encapsulate enums within a Node. Checkout the Schema Appliances guide and the API for IdioEnum.

const StatusEnum = new IdioEnum({
    name: "StatusEnum",
    ...
});


const User = new GraphQLNode({
    name: "User",
    enums: [ StatusEnum ],
    ...
});

Interfaces

---

You can encapsulate interfaces within a Node. Checkout the Schema Appliances guide and the API for IdioInterface.

const PersonInterface = new IdioInterface({
    name: "PersonInterface",
    ...
});


const User = new GraphQLNode({
    name: "User",
    interfaces: [ PersonInterface ],
    ...
});

Unions

---

You can encapsulate unions within a Node. Checkout the Schema Appliances guide and the API for IdioUnion.

const UserUnion = new IdioUnion({
    name: "UserUnion",
    ...
});


const User = new GraphQLNode({
    name: "User",
    unions: [ UserUnion ],
    ...
});

Types

---

You can encapsulate types within a Node. Checkout the Schema Appliances guide and the API for GraphQLType.

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


const User = new GraphQLNode({
    name: "User",
    types: [ Metadata ],
    ...
});