Pagination helper method for TypeORM repostiories or queryBuilders with strict typings

Install

$ yarn add nestjs-typeorm-paginate

Usage

Service

Repository

import {Injectable} from '@nestjs/common';
import {Repository} from 'typeorm';
import {InjectRepository} from '@nestjs/typeorm';
import {CatEntity} from './entities';
import {paginate, Pagination, IPaginationOptions} from 'nestjs-typeorm-paginate';

@Injectable()
export class CatService {
  constructor (
    @InjectRepository(CatEntity) private readonly repository: Repository<CatEntity>,
  ) {}

  async paginate(options: IPaginationOptions): Promise<Pagination<CatEntity>> {
    return paginate<CatEntity>(this.repository, options);
  }
}

QueryBuilder

import {Injectable} from '@nestjs/common';
import {Repository} from 'typeorm';
import {InjectRepository} from '@nestjs/typeorm';
import {CatEntity} from './entities';
import {paginate, Pagination, IPaginationOptions} from 'nestjs-typeorm-paginate';

@Injectable()
export class CatService {
  constructor (
    @InjectRepository(CatEntity) private readonly repository: Repository<CatEntity>,
  ) {}

  async paginate(options: IPaginationOptions): Promise<Pagination<CatEntity>> {
    const queryBuilder = this.repository.createQueryBuilder('c');
    queryBuilder.orderBy('c.name', 'DESC'); // Or whatever you need to do

    return paginate<CatEntity>(queryBuilder, options);
  }
}

Controller

import {Controller, Get, Query} from '@nestjs/common';
import {CatService} from './cat.service';
import {CatEntity} from './cat.entity';
import {Pagination} from 'nestjs-typeorm-paginate';

@Controller('cats')
export class CatsController {
  constructor(private readonly catService: CatService) {}
  @Get('')
  async index(
    @Query('page') page: number = 1, 
    @Query('limit') limit: number = 10,
  ): Pagination<CatEntity> {
    limit = limit > 100 ? 100 : limit;
    return this.catService.paginate({
      page,
      limit,
      route: 'http://cats.com/cats',
    });
  }
}

Example Response

{
  "items": [
    {
      "lives": 9,
      "type": "tabby",
      "name": "Bobby"
    },
    {
      "lives": 2,
      "type": "Ginger",
      "name": "Garfield"
    },
    {
      "lives": 6,
      "type": "Black",
      "name": "Witch's mate"
    },
    {
      "lives": 7,
      "type": "Purssian Grey",
      "name": "Alisdaya"
    },
    {
      "lives": 1,
      "type": "Alistair",
      "name": "ali"
    },
    ...
  ],
  "meta": {
    "itemCount": 10, 
    "totalItems": 20,
    "itemsPerPage": 10,
    "totalPages": 5,
    "currentPage": 2
  },
  "links" : {
    "first": "http://cats.com/cats?limit=10",
    "previous": "http://cats.com/cats?page=1&limit=10",
    "next": "http://cats.com/cats?page=3&limit=10",
    "last": "http://cats.com/cats?page=5&limit=10"
  }
}

items: An array of SomeEntity

meta.itemCount: The length of items array (i.e., the amount of items on this page) meta.totalItems: The total amount of SomeEntity matching the filter conditions meta.itemsPerPage: The requested items per page (i.e., the limit parameter)

meta.totalPages: The total amount of pages (based on the limit) meta.currentPage: The current page this paginator "points" to

links.first: A URL for the first page to call | "" (blank) if no route is defined links.previous: A URL for the previous page to call | "" (blank) if no previous to call
links.next: A URL for the next page to call | "" (blank) if no page to call
links.last: A URL for the last page to call | "" (blank) if no route is defined

Find Parameters

@Injectable()
export class CatService {
  constructor (
    @InjectRepository(CatEntity) private readonly repository: Repository<CatEntity>,
  ) {}

  async paginate(options: IPaginationOptions): Promise<Pagination<CatEntity>> {
    return paginate<CatEntity>(this.repository, options, {
        lives: 9,
    });
  }
}

Eager loading

Eager loading should work with typeorm's eager property out the box. Like so

import {Entity, OneToMany} from 'typeorm';

@Entity()
export class CatEntity {

  @OneToMany(t => TigerKingEntity, tigerKing.cats, {
    eager: true,
  })
  tigerKings: TigerKingEntity[];
}


// service 
class CatService {
  constructor(
    private readonly repository: Repository<CatEntity>,
  ) {}

  async paginate(page: number, limit: number): Promise<Pagination<CatEntity>> {
   return paginate(this.repository, {page, limit});
  }
}

QueryBuilder

However, when using the query builder you'll have to hydrate the entities yourself. Here is a crud example that I've used in the past.

const results = paginate(queryBuilder, {page, limit});

return new Pagination(
  await Promise.all(results.items.map(async (item: SomeEntity) => {
    const hydrate = await this.someRepository.findByEntity(item);
    item.hydrated = hydrate;

    return item;
  })),
  results.meta,
  results.links,
);