join-monster

{
  "user": {
    "fullName": "Yasmine Rolfson",
    "email": "Earl.Koss41@yahoo.com",
    "posts": [
      {
        "id": 2,
        "body": "Harum unde maiores est quasi totam consequuntur. Necessitatibus doloribus ut totam dolore omnis quos error eos. Rem nostrum assumenda eius veniam fugit dicta in consequuntur. Ut porro dolorem aliquid qui magnam a.",
        "comments": [
          {
            "body": "The AI driver is down, program the multi-byte sensor so we can parse the SAS bandwidth!",
            "author": { "fullName": "Yasmine Rolfson" }
          },
          {
            "body": "Try to program the SMS transmitter, maybe it will synthesize the optical firewall!",
            "author": { "fullName": "Ole Barrows" }
          },
        ]
      },
      // other posts omitted for clarity...
    ]
  }
}

import joinMonster from 'join-monster'
import {
  GraphQLObjectType,
  GraphQLList,
  GraphQLString,
  GraphQLInt
  // and some other stuff
} from 'graphql'

const User = new GraphQLObjectType({
  name: 'User',
  sqlTable: 'accounts', // the SQL table for this object type is called "accounts"
  uniqueKey: 'id', // the id in each row is unique for this table
  fields: () => ({
    id: {
      // the column name is assumed to be the same as the field name
      type: GraphQLInt
    },
    email: {
      type: GraphQLString,
      // if the column name is different, it must be specified specified
      sqlColumn: 'email_address'
    },
    idEncoded: {
      description: 'The ID base-64 encoded',
      type: GraphQLString,
      // this field uses a sqlColumn and applies a resolver function on the value
      // if a resolver is present, the `sqlColumn` MUST be specified even if it is the same name as the field
      sqlColumn: 'id',
      resolve: user => toBase64(user.idEncoded)
    },
    fullName: {
      description: "A user's first and last name",
      type: GraphQLString,
      // perhaps there is no 1-to-1 mapping of field to column
      // this field depends on multiple columns
      sqlDeps: [ 'first_name', 'last_name' ],
      // compute the value with a resolver
      resolve: user => `${user.first_name} ${user.last_name}`
    },
    capitalizedLastName: {
      type: GraphQLString,
      // do a computed column in SQL with raw expression
      sqlExpr: (table, args) => `UPPER(${table}.last_name)`
    },
    // got tables inside tables??
    // get it with a JOIN!
    posts: {
      description: "A List of posts this user has written.",
      type: new GraphQLList(Post),
      // a function to generate the join condition from the table aliases
      sqlJoin(userTable, postTable) {
        return `${userTable}.id = ${postTable}.author_id`
      }
    },
    // got a relationship but don't want to add another JOIN?
    // get this in a second batch request
    comments: {
      description: "The comment they have written",
      type: new GraphQLList(Comment),
      // specify which columns to match up the values
      sqlBatch: {
        thisKey: 'author_id',
        parentKey: 'id'
      }
    },
    // many-to-many relations are supported too
    following: {
      description: "Other users that this user is following.",
      type: new GraphQLList(User),
      // name the table that holds the two foreign keys
      junction: {
        sqlTable: 'relationships',
        sqlJoins: [
          // first the parent table to the junction
          (followerTable, junctionTable, args) => `${followerTable}.id = ${junctionTable}.follower_id`,
          // then the junction to the child
          (junctionTable, followeeTable, args) => `${junctionTable}.followee_id = ${followeeTable}.id`
        ]
      }
    },
    numLegs: {
      description: 'Number of legs this user has.',
      type: GraphQLInt,
      // data isn't coming from the SQL table? no problem! joinMonster will ignore this field
      resolve: () => 2
    }
  })
})

const Comment = new GraphQLObjectType({
  name: 'Comment',
  sqlTable: 'comments',
  uniqueKey: 'id',
  fields: () => ({
    // id and body column names are the same
    id: {
      type: GraphQLInt
    },
    body: {
      type: GraphQLString
    }
  })
})

const Post = new GraphQLObjectType({
  name: 'Post',
  sqlTable: 'posts',
  uniqueKey: 'id',
  fields: () => ({
    id: {
      type: GraphQLInt
    },
    body: {
      type: GraphQLString
    }
  })
})

export const QueryRoot = new GraphQLObjectType({
  name: 'Query',
  fields: () => ({
    // place this user type in the schema
    user: {
      type: User,
      // let client search for users by `id`
      args: {
        id: { type: GraphQLInt }
      },
      // how to write the WHERE condition
      where: (usersTable, args, context) => {
        if (args.id) return `${usersTable}.id = ${args.id}`
      },
      resolve: (parent, args, context, resolveInfo) => {
        // resolve the user and the comments and any other descendants in a single request and return the data!
        // all you need to pass is the `resolveInfo` and a callback for querying the database
        return joinMonster(resolveInfo, {}, sql => {
          // knex is a query library for SQL databases
          return knex.raw(sql)
        })
      }
    }
  })
})