nexus-pagination-plugin

nexus-pagination-plugin

nexus-pagination-plugin

---

This pagination plugin provides a new method on the object definition builder, enabling paginated associations between types, following the offset-based pagination standard defined below.

Offset-Based Pagination Standard

A paginated query field should receive two arguments:

• page
  • The current page being request. Defaults to 1
• pageSize
  • The size of pages being used. Defaults to 25

A paginated query field should return a type that contains the following:

• results
  • A collection of the data requested
• pageInfo
  • A type that contains information about the pagination
  • page
  • nextPage
  • totalPages

Installation

yarn add nexus-pagination-plugin

or

npm install nexus-pagination-plugin

Setup

import { makeSchema} from 'nexus';
import { paginationPlugin } from 'nexus-pagination-plugin';

export const schema = makeSchema({
  // ... types, etc,
  plugins: [
    // ... other plugins
    paginationPlugin()
  ],
});

Example Usage

This plugin surfaces a t.paginatedQueryResult function that can be used to add pagination to a given type.

// User Type
export const User = objectType({
  name: 'User',
  description: 'A User',
  definition(t) {
    t.nonNull.id('id');
    t.nonNull.string('firstName');
    t.nonNull.string('lastName');
  },
});

// add paginated users query
export const UsersQuery = queryField((t) => {
  t.paginatedQueryResult('users', {
    type: 'User',
    resolve: async (_root, args, ctx) => {
      const { take, skip } = ctx.paginationParams;

      const users = await ctx.prisma.user.findMany({
        skip,
        take,
      });
      const usersCount = await ctx.prisma.user.count();
      const pageInfo = ctx.calculatePageInfo(usersCount);

      return {
        results: users,
        pageInfo
      }
    },
  })
})

resolve: (root, args, ctx) => ...

t.paginatedQueryResult wraps the resolve function passed in the query config and adds the following fields on the context object.

ctx.paginationParams: {take: number, skip: number}

• take specifies the page size
• skip specifies how many to skip based on the page size and page arguments

ctx.calculatePageInfo: (count: number) => PageInfo

• count specifies the total count of records in the DB
• Returns type PageInfo

Generated Types

PageInfo

objectType({
  name: 'PageInfo',
  definition(t) {
    t.int('page');
    t.int('nextPage');
    t.int('totalPages');
  },
})

Paginated${targeTypename}s

objectType({
  name: generatedTypeName,
  definition(t2) {
    t2.nonNull.list.field('results', {
      type: fieldConfig.type,
      description: `Collection of ${fieldName}`,
    });

    t2.nonNull.field('pageInfo', {
      type: 'PageInfo',
      description: 'Pagination information',
    });
  },
})

For a paginated field defined on Query like this:

queryField((t) => {
  t.paginatedQueryField('foos', {
    type: 'Foo',
    // ... any additional query config
  });
});

The following types would be generated:

type PageInfo {
  nextPage: Int
  page: Int
  totalPages: Int
}

type PaginatedFoos {
  pageInfo: PageInfo!
  results: [Foo]!
}

type Query {
  """ ... other Query fields """

  foos(
    page: Int = 1,
    pageSize: Int = 25
  ): PaginatedFoos
}

Note that the collection type will be added to whatever parent type is specified. This means that if you were to define a paginated field on another object rather than on Query like this:

objectType({
  type: 'Bar',
  definition(t) {
    // ... other definitions
    t.paginatedQueryField('foos', {
      type: 'Foo',
      // ... any additional query config
    });
  }
})

The foos query would be added to the Bar type rather than the Query type:

type Bar {
  """ ... other Bar fields """

  foos(
    page: Int = 1
    pageSize: Int = 25
  ): PaginatedFoos
}

Options

defaultPageSize: number

Used to specify a different default for the generated pageSize argument. Defaults to 25

Global usage:

paginationPlugin({
  defaultPageSize: 10
})

Field usage:

export const UsersQuery = queryField((t) => {
  t.paginatedQueryResult('users', {
    // ... any additional query fields
    defaultPageSize: 10
  })  
})

getGeneratedTypename: (targetTypename: string) => string

Used to specify a different generated typename for the paginated types. Defaults to Paginated${targetTypename}s

Usage:

paginationPlugin({
  getGeneratedTypename: (targetTypename) => `${targetTypename}sPaginated`
})

generatedTypename: string

Used to specify a different generated typename for a specific field. Defaults to Paginated${targetTypename}s or whatever is defined by getGeneratedTypename

Usage:

export const FinishesQuery = queryField((t) => {
  t.paginatedQueryResult('finishes', {
    type: 'Finish',
    // ... any additional query fields
    generatedTypename: 'PaginatedFinishes'
  })
})