Join Monster V2

New features:

• LIMIT functionality, supported on all fields
• Fetch columns from junction tables
• For fields with junctions, you can now specify WHERE and ORDER BY clauses on the junction table or the main table, including paginated fields.
• Ability to dynamically choose pagination implementation per-request.
• Better ability to write where functions that depend on args and info from the parent/ancestors.

Breaking changes:

• Fields with junctions have a new interface in order to support the new features.
• Any where, orderBy, and sortKey on many-to-many paginated fields used to be applied to the junction table. This has changed, and will be applied to the main table instead in order to be consistent with non-paginated junctions. If the old behavior is desired, you can nest those properties inside the junction object, which is part of the new API.
• Change 4th parameter of where and sqlExpr to the field's SQL AST Node, which is a lot more useful.

// this...
{
  type: new GraphQLList(User),
  junctionTable: 'relationships',
  sqlJoins: [
    (followers, relations) => `${followers}.id = ${relations}.follower_id`,
    (relations, followees) => `${relations}.followee_id = ${followees}.id`
  ]
}

// is now this...
{
  type: new GraphQLList(User),
  junction: {
    sqlTable: 'relationships',
    sqlJoins: [
      (followers, relations) => `${followers}.id = ${relations}.follower_id`,
      (relations, followees) => `${relations}.followee_id = ${followees}.id`
    ]
  }
}

// this...
{
  type: new GraphQLList(User),
  junctionTable: 'relationships',
  junctionTableKey: [ 'follower_id', 'followee_id' ],
  junctionBatch: {
    thisKey: 'follower_id',
    parentKey: 'id',
    sqlJoin: (relations, followees) => `${relations}.followee_id = ${followees}.id`
  }
}

// is now this...
{
  type: new GraphQLList(User),
  junction: {
    sqlTable: 'relationships',
    uniqueKey: [ 'follower_id', 'followee_id' ],
    sqlBatch: {
      thisKey: 'follower_id',
      parentKey: 'id',
      sqlJoin: (relations, followees) => `${relations}.followee_id = ${followees}.id`
    }
  }
}

// this...
{
  type: UserConnection,
  args: forwardConnectionArgs,
  sqlPaginate: true,
  orderBy: {
    created_at: 'DESC',
    followee_id: 'ASC'
  },
  junctionTable: 'relationships',
  sqlJoins: [
    (followers, relations) => `${followers}.id = ${relations}.follower_id`,
    (relations, followees) => `${relations}.followee_id = ${followees}.id`
  ]
}

// is now this...
{
  type: UserConnection,
  args: forwardConnectionArgs,
  sqlPaginate: true,
  junction: {
    sqlTable: 'relationships',
    sqlJoins: [
      (followers, relations) => `${followers}.id = ${relations}.follower_id`,
      (relations, followees) => `${relations}.followee_id = ${followees}.id`
    ],
    // the order now goes inside the `junction` if you want to sort on the junction table
    orderBy: {
      created_at: 'DESC',
      followee_id: 'ASC'
    }
  }
  // or you could apply the order on the user table by putting it out here
  //orderBy: {
  //  created_at: 'DESC',
  //  id: 'ASC'
  //}
  
  // you could also place a `where` at either
}